A068043 Number of subsets of {1,2,3,...,n} that sum to 0 mod 25.

1, 1, 1, 1, 1, 1, 1, 3, 10, 23, 43, 82, 164, 328, 656, 1312, 2622, 5243, 10486, 20972, 41945, 83887, 167773, 335546, 671092, 1342184, 2684360, 5368712, 10737422, 21474842, 42949682, 85899350, 171798690, 343597388, 687194782, 1374389558

Offset: 0

Author

Antti Karttunen, Feb 11 2002

Keywords

• nonn

Crossrefs

25th row of A068009.

Formula

Empirical G.f.: -(x -1) * (4*x^29 +4*x^28 +4*x^27 -4*x^24 -4*x^23 -4*x^22 -3*x^21 -2*x^20 -x^19 -x^18 -x^17 -2*x^16 +4*x^15 +10*x^14 +4*x^13 -4*x^12 -6*x^11 -8*x^10 -9*x^9 -4*x^8 +2*x^7 +5*x^6 +6*x^5 +3*x^4 +2*x^3 +x^2 -1) / ((2*x -1)*(2*x^5 -1)*(2*x^25 -1)). [Colin Barker, Dec 23 2012]