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A239426 21*n^4 - 36*n^3 + 25*n^2 - 8*n + 1. 4
1, 3, 133, 931, 3441, 9211, 20293, 39243, 69121, 113491, 176421, 262483, 376753, 524811, 712741, 947131, 1235073, 1584163, 2002501, 2498691, 3081841, 3761563, 4547973, 5451691, 6483841, 7656051, 8980453, 10469683, 12136881, 13995691, 16060261, 18345243 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
For n > 0: a(n) = A219069(2*n-1,n).
LINKS
FORMULA
a(n) = (1-3*n+3*n^2) * (1-5*n+7*n^2) = A003215(n-1) * A239449(n).
G.f.: ( -1+2*x-128*x^2-286*x^3-91*x^4 ) / (x-1)^5 . - R. J. Mathar, Mar 31 2014
MATHEMATICA
Table[(21 n^4 - 36 n^3 + 25 n^2 - 8 n + 1), {n, 0, 40}] (* Vincenzo Librandi, Mar 21 2014 *)
LinearRecurrence[{5, -10, 10, -5, 1}, {1, 3, 133, 931, 3441}, 40] (* Harvey P. Dale, May 04 2016 *)
PROG
(Haskell)
a239426 n = (((21 * n - 36) * n + 25) * n - 8) * n + 1
(Magma) [21*n^4-36*n^3+25*n^2-8*n+1: n in [0..31]]; // Vincenzo Librandi, Mar 21 2014
CROSSREFS
Sequence in context: A213203 A199141 A152435 * A157086 A366306 A051376
KEYWORD
nonn,easy
AUTHOR
Reinhard Zumkeller, Mar 19 2014
STATUS
approved

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Last modified May 25 17:00 EDT 2024. Contains 372804 sequences. (Running on oeis4.)