OFFSET
0,4
LINKS
Z.-W. Sun, Congruences for Franel numbers, arXiv preprint arXiv:1112.1034, 2011. See Eq. 1.5.
FORMULA
Conjecture: (n-1)^2*a(n) +(2*n-3)*(3*n-5)*a(n-1) +(-15*n^2+53*n-48)*a(n-2) +8*(n-2)^2*a(n-3)=0. - R. J. Mathar, Nov 28 2013
a(n) ~ (-1)^(n+1) * sqrt(3) * 2^(3*n+1) / (27*Pi*n). - Vaclav Kotesovec, Jan 31 2014
MATHEMATICA
Flatten[{0, Table[Sum[(-1)^k*Sum[Binomial[k, j]^3, {j, 0, k}], {k, 0, n-1}], {n, 1, 20}]}] (* Vaclav Kotesovec, Jan 31 2014 *)
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Feb 16 2012
STATUS
approved