A271859 - OEIS

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A271859

Six steps forward, five steps back.

0, 1, 2, 3, 4, 5, 6, 5, 4, 3, 2, 1, 2, 3, 4, 5, 6, 7, 6, 5, 4, 3, 2, 3, 4, 5, 6, 7, 8, 7, 6, 5, 4, 3, 4, 5, 6, 7, 8, 9, 8, 7, 6, 5, 4, 5, 6, 7, 8, 9, 10, 9, 8, 7, 6, 5, 6, 7, 8, 9, 10, 11, 10, 9, 8, 7, 6, 7, 8, 9, 10, 11, 12, 11, 10, 9, 8, 7, 8, 9, 10, 11

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OFFSET

0,3

LINKS

Colin Barker, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,0,0,0,0,0,1,-1).

FORMULA

a(n) = a(n-1) + a(n-11) - a(n-12) for n>11.

a(n) = Sum_{i=1..n} (-1)^floor((2*i-2)/11).

G.f.: x*(1+x+x^2+x^3+x^4+x^5-x^6-x^7-x^8-x^9-x^10) / ((1-x)^2*(1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9+x^10)). - Colin Barker, Apr 16 2016

MAPLE

A271859:=n->add((-1)^floor((2*i-2)/11), i=1..n): seq(A271859(n), n=0..200);

MATHEMATICA

Table[Sum[(-1)^Floor[(2 i - 2)/11], {i, n}], {n, 0, 100}]

PROG

(PARI) concat(0, Vec(x*(1+x+x^2+x^3+x^4+x^5-x^6-x^7-x^8-x^9-x^10) / ((1-x)^2*(1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9+x^10)) + O(x^50))) \\ Colin Barker, Apr 16 2016

CROSSREFS

Cf. A008611 (one step back, two steps forward).

Cf. A058207 (three steps forward, two steps back).

Cf. A260644 (four steps forward, three steps back).

Cf. A271800 (five steps forward, four steps back).

Sequence in context: A134665 A271832 A063260 * A232240 A073793 A017891

Adjacent sequences: A271856 A271857 A271858 * A271860 A271861 A271862

KEYWORD

nonn,easy

AUTHOR

Wesley Ivan Hurt, Apr 15 2016

STATUS

approved