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A128786 n^2*7^n. 1
0, 7, 196, 3087, 38416, 420175, 4235364, 40353607, 368947264, 3268642167, 28247524900, 239256535903, 1993145356944, 16374242758783, 132931722278404, 1068201339737175, 8507630225817856, 67230218542302823, 527606005722985476 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
FORMULA
G.f.: 7*x*(1 + 7*x)/((1 - 7*x)^3). - Vincenzo Librandi, Feb 06 2013
a(n) = 21*a(n-1) - 147*a(n-2) + 343*a(n-3). - Vincenzo Librandi, Feb 06 2013
MATHEMATICA
LinearRecurrence[{21, -147, 343}, {0, 7, 196}, 40] (* Vincenzo Librandi, Feb 06 2013 *)
PROG
(Magma) [n^2*7^n: n in [0..20]]; // Vincenzo Librandi, Feb 06 2013
CROSSREFS
Sequence in context: A135809 A182268 A156359 * A034835 A041371 A136675
KEYWORD
nonn,easy
AUTHOR
Mohammad K. Azarian, Apr 07 2007
STATUS
approved

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Last modified March 28 20:05 EDT 2024. Contains 371254 sequences. (Running on oeis4.)