A068036 Number of subsets of {1,2,3,...,n} that sum to 0 mod 15.

1, 1, 1, 1, 1, 2, 5, 9, 18, 36, 70, 138, 276, 548, 1096, 2192, 4374, 8744, 17486, 34958, 69916, 139830, 279630, 559260, 1118520, 2236988, 4473964, 8947920, 17895736, 35791472, 71582944, 143165660, 286331296, 572662588, 1145324764, 2290649528

Offset

0,6

Links

Table of n, a(n) for n=0..35.

Formula

Empirical G.f.: -(8*x^23 +4*x^21 -8*x^20 +4*x^19 -4*x^18 +2*x^17 -4*x^16 +2*x^15 -8*x^14 +2*x^12 +8*x^11 +4*x^10 +4*x^9 -6*x^8 -3*x^7 -5*x^6 -x^4 +3*x^3 +x^2 +x -1) / ((2*x-1) * (2*x^3-1) * (2*x^5-1) * (2*x^15-1)). - Colin Barker, Dec 22 2012

Crossrefs

15th row of A068009.

Sequence in context: A097281 A321408 A289976 * A364525 A077947 A077972

Adjacent sequences: A068033 A068034 A068035 * A068037 A068038 A068039

Keyword

nonn

Author

Antti Karttunen, Feb 11 2002

Status

approved