OFFSET
0,2
COMMENTS
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (5,-10,10,-5,1).
FORMULA
G.f.: (1-9*x+71*x^2+61*x^3-4*x^4)/(1-x)^5. - Bruno Berselli, Mar 01 2012
a(n) = 5*n^4-10*n^2+1. - Bruno Berselli, Mar 01 2012
a(n) = (1+n^2)^(5/2)*cos(5*arctan(n)). - Gerry Martens, Apr 06 2024
EXAMPLE
a(4) = 1121 since (1 + 4i)^5 = (1121 + 404i) where 404 = A121672(4).
MATHEMATICA
Table[Re[(1 + n*I)^5], {n, 0, 35}] (* T. D. Noe, Mar 01 2012 *)
LinearRecurrence[{5, -10, 10, -5, 1}, {1, -4, 41, 316, 1121}, 40] (* Harvey P. Dale, Apr 21 2019 *)
PROG
(PARI) a(n) = real((1 + n*I)^5); \\ Michel Marcus, Dec 19 2020
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Gary W. Adamson, Aug 14 2006
EXTENSIONS
Corrected and extended by T. D. Noe, Mar 01 2012
STATUS
approved