A309299 (1/7) times the sum of the elements of all subsets of [n] whose sum is divisible by seven.

0, 0, 0, 0, 2, 5, 15, 40, 97, 237, 571, 1385, 3263, 7618, 17580, 40146, 90962, 204618, 457446, 1016494, 2247000, 4943400, 10828248, 23625120, 51358776, 111277576, 240359368, 517697136, 1112090144, 2383049792, 5094795600, 10868896688, 23140232368, 49172993152

Offset

0,5

Links

Alois P. Heinz, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (6,-12,8,0,0,0,6,-36,72,-48,0,0,0,-12,72,-144,96,0,0,0,8,-48,96,-64).

Formula

G.f.: -x^4*(8*x^18+24*x^14-12*x^12+4*x^11+16*x^10-38*x^9+49*x^8 -15*x^7 +7*x^6 -15*x^5 +3*x^4 +6*x^3 -9*x^2+7*x-2) / ((2*x-1)^3 *(2*x^7-1)^3).

Crossrefs

Column k=7 of A309280.

Sequence in context: A148345 A148346 A148347 * A151260 A148348 A148349

Adjacent sequences: A309296 A309297 A309298 * A309300 A309301 A309302

Keyword

nonn,easy

Author

Alois P. Heinz, Jul 21 2019

Status

approved