OFFSET
1,2
REFERENCES
E. R. Berlekamp, J. H. Conway and R. K. Guy, Winning Ways, Academic Press, NY, 2 vols., 1982; p. 810.
LINKS
Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).
FORMULA
From Harvey P. Dale, Jun 10 2011: (Start)
G.f.: (x*(x*(x+3)*(x+20)+23)+1)/(1-x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5), a(0) = 1, a(1) = 28, a(2) = 190, a(3) = 703, a(4) = 1891. (End)
a(n) = (3*n^2 - 3*n + 1)*(3*n^2 - 3*n + 2)/2. - Bruno Berselli, Jan 28 2017
MATHEMATICA
Table[(9n^4 + 18n^2 + 5)/32, {n, 1, 71, 2}] (* or *) LinearRecurrence[ {5, -10, 10, -5, 1}, {1, 28, 190, 703, 1891}, 36] (* Harvey P. Dale, Jun 10 2011 *)
PROG
(PARI) a(n)=(((9*n-18)*n+18)*n-9)*n/2+1 \\ Charles R Greathouse IV, Jun 10 2011
(Magma) [(9*n^4 - 18*n^3 + 18*n^2 - 9*n + 2)/2 : n in [1..40]]; // Wesley Ivan Hurt, Jan 27 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Feb 21 2003
STATUS
approved