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A015509 a(1)=1, a(n) = sum_{k=1}^{k=n-1} (8^k-1)/7 a(k). 0
1, 1, 10, 740, 433640, 2030302480, 76034827876000, 22779578222682344000, 54596862986901017252624000, 1046838176230046602563156976288000, 160576277008444677145920980328106246720000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..11.

FORMULA

a(n) = ((8^(n-1) + 6)/7) * a(n-1). - Vincenzo Librandi, Nov 12 2012

PROG

(MAGMA) I:=[1, 1, 10]; [n le 3 select I[n] else ((8^(n-1) + 6)/7) * Self(n-1): n in [1..15]]; // Vincenzo Librandi, Nov 12 2012

CROSSREFS

Sequence in context: A108603 A053468 A008272 * A117257 A030979 A183288

Adjacent sequences:  A015506 A015507 A015508 * A015510 A015511 A015512

KEYWORD

nonn,easy

AUTHOR

Olivier Gérard

STATUS

approved

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Last modified June 27 16:00 EDT 2022. Contains 354896 sequences. (Running on oeis4.)