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A178186 Sum 3^((k^2+3k)/2) from k=1 to n. 1
9, 252, 19935, 4802904, 3491587305, 7629089072292, 50039174188071999, 984820941357799304880, 58150721823981417489695049, 10301109611599361435391036962892, 5474411390529830981438591324606714655 (list; graph; refs; listen; history; text; internal format)
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..60

MATHEMATICA

aa = {}; m = 3; sum = 0; Do[sum = sum + m^((n + 3) n/2); AppendTo[aa, sum], {n, 1, 20}]; aa (*Artur Jasinski*)

PROG

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

CROSSREFS

Cf. A178184-A178193.

Sequence in context: A158621 A256019 A135484 * A212290 A296950 A025133

Adjacent sequences:  A178183 A178184 A178185 * A178187 A178188 A178189

KEYWORD

nonn

AUTHOR

Artur Jasinski, May 21 2010

STATUS

approved

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Last modified May 22 14:32 EDT 2019. Contains 323480 sequences. (Running on oeis4.)