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Revision History for A289163

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Showing entries 1-10 | older changes
Number of 5-cycles in the n X n black bishop graph.
(history; published version)
#11 by Bruno Berselli at Wed Jun 28 08:44:52 EDT 2017
STATUS

reviewed

approved

#10 by Michel Marcus at Wed Jun 28 08:18:57 EDT 2017
STATUS

proposed

reviewed

#9 by Colin Barker at Wed Jun 28 08:15:46 EDT 2017
STATUS

editing

proposed

#8 by Colin Barker at Wed Jun 28 08:15:28 EDT 2017
LINKS

Colin Barker, <a href="/A289163/b289163.txt">Table of n, a(n) for n = 1..1000</a>

FORMULA

G.f.: 2*x^34*(5 + 32*x + 57*x^2 + 146*x^3 + 19*x^4 + 104*x^5 + 15*x^6 + 6*x^7) / ((1 - x)^7*(1 + x)^5). - Colin Barker, Jun 27 2017

PROG

(PARI) concat(vector(3), Vec(2*x^34*(5 + 32*x + 57*x^2 + 146*x^3 + 19*x^4 + 104*x^5 + 15*x^6 + 6*x^7) / ((1 - x)^7*(1 + x)^5) + O(x^40))) \\ Colin Barker, Jun 27 2017

STATUS

approved

editing

#7 by N. J. A. Sloane at Tue Jun 27 08:35:59 EDT 2017
STATUS

proposed

approved

#6 by Colin Barker at Tue Jun 27 06:35:41 EDT 2017
STATUS

editing

proposed

#5 by Colin Barker at Tue Jun 27 06:34:54 EDT 2017
LINKS

<a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (2,4,-10,-5,20,0,-20,5,10,-4,-2,1).

FORMULA

a(n) = 2*a(n-1)+4*a(n-2)-10*a(n-3)-5*a(n-4)+20*a(n-5)-20*a(n-7)+5*a(n-8)+10*a(n-9)-4*a(n-10)-2*a(n-11)++a(n-12).

G.f.: 2*x^3*(5 + 32*x + 57*x^2 + 146*x^3 + 19*x^4 + 104*x^5 + 15*x^6 + 6*x^7) / ((1 - x)^7*(1 + x)^5). - Colin Barker, Jun 27 2017

PROG

(PARI) concat(vector(3), Vec(2*x^3*(5 + 32*x + 57*x^2 + 146*x^3 + 19*x^4 + 104*x^5 + 15*x^6 + 6*x^7) / ((1 - x)^7*(1 + x)^5) + O(x^40))) \\ Colin Barker, Jun 27 2017

KEYWORD

nonn,changed,easy

STATUS

proposed

editing

Discussion
Tue Jun 27
06:35
Colin Barker: Fixed typo in second formula.
#4 by Eric W. Weisstein at Mon Jun 26 15:18:49 EDT 2017
STATUS

editing

proposed

#3 by Eric W. Weisstein at Mon Jun 26 15:18:46 EDT 2017
CROSSREFS

Cf. A289161 (3-cycles), A289162 (4-cycles), A289160 (6-cycles).

#2 by Eric W. Weisstein at Mon Jun 26 15:16:44 EDT 2017
NAME

allocated for Eric W. Weisstein

Number of 5-cycles in the n X n black bishop graph.

DATA

0, 0, 0, 10, 84, 322, 1172, 2780, 7016, 13532, 27720, 47318, 84796, 133294, 217756, 322392, 492240, 696216, 1009680, 1377474, 1918500, 2541946, 3426852, 4431988, 5816888, 7371572, 9460568, 11782862, 14837004, 18204326, 22551340, 27310384, 33355168, 39932592, 48168480

OFFSET

1,4

LINKS

Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/BlackBishopGraph.html">Black Bishop Graph</a>

Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/GraphCycle.html">Graph Cycle</a>

FORMULA

a(n) = (-165 - 282*n + 972*n^2 - 730*n^3 + 280*n^4 - 68*n^5 + 8*n^6 - 5*(-1)^n*(-33 - 26*n + 96*n^2 - 46*n^3 + 6*n^4))/240.

a(n) = 2*a(n-1)+4*a(n-2)-10*a(n-3)-5*a(n-4)+20*a(n-5)-20*a(n-7)+5*a(n-8)+10*a(n-9)-4*a(n-10)-2*a(n-11)++a(n-12).

MATHEMATICA

Table[(-165 - 282 n + 972 n^2 - 730 n^3 + 280 n^4 - 68 n^5 + 8 n^6 - 5 (-1)^n (-33 - 26 n + 96 n^2 - 46 n^3 + 6 n^4))/240, {n, 20}]

LinearRecurrence[{2, 4, -10, -5, 20, 0, -20, 5, 10, -4, -2, 1}, {0, 0, 0, 10, 84, 322, 1172, 2780, 7016, 13532, 27720, 47318}, 20]

KEYWORD

allocated

nonn

AUTHOR

Eric W. Weisstein, Jun 26 2017

STATUS

approved

editing