A178192 Sum 11^((k^2+3k)/2) from k=1 to n.

121, 161172, 2358108863, 379752191692104, 672750374684751701305, 13109994864250305051813161676, 2810243697916419649311518955166566527, 6626407610546884801816680266380777080570215568

Offset

1,1

Comments

Series of the kind m^((k^2+3k)/2) from k=1 to n was studied by Bernoulli and Euler.

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..40

Mathematica

aa = {}; m = 11; sum = 0; Do[sum = sum + m^((n + 3) n/2); AppendTo[aa, sum], {n, 1, 20}]; aa (*Artur Jasinski*)
Table[11^((k^2+3k)/2), {k, 10}]//Accumulate (* Harvey P. Dale, Apr 02 2020 *)

Prog

(PARI) a(n) = sum(k=1, n, 11^((k^2+3*k)/2)); \\ Michel Marcus, Sep 09 2013

Crossrefs

Cf. A178184-A178193.

Sequence in context: A360504 A028463 A013749 * A135825 A221392 A337728

Adjacent sequences: A178189 A178190 A178191 * A178193 A178194 A178195

Keyword

nonn

Author

Artur Jasinski, May 21 2010

Status

approved