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A014905 a(1)=1, a(n) = 21*a(n-1) + n. 2
1, 23, 486, 10210, 214415, 4502721, 94557148, 1985700116, 41699702445, 875693751355, 18389568778466, 386180944347798, 8109799831303771, 170305796457379205, 3576421725604963320, 75104856237704229736 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..200

Index entries for linear recurrences with constant coefficients, signature (23, -43, 21).

FORMULA

a(n) = -21/400 - (1/20)*n + (21/400)*21^n, with n >= 1. - Paolo P. Lava, Jan 14 2009

a(1)=1, a(2)=23, a(3)=486, a(n) = 23*a(n-1) - 43*a(n-2) + 21*a(n-3). - Vincenzo Librandi, Oct 19 2012

MATHEMATICA

LinearRecurrence[{23, -43, 21}, {1, 23, 486}, 20] (* Vincenzo Librandi, Oct 19 2012 *)

PROG

(MAGMA) I:=[1, 23, 486]; [n le 3 select I[n] else 23*Self(n-1) - 43*Self(n-2)+ 21*Self(n-3): n in [1..20]]; // Vincenzo Librandi, Oct 19 2012

CROSSREFS

Sequence in context: A273008 A015678 A293083 * A200734 A218715 A133283

Adjacent sequences:  A014902 A014903 A014904 * A014906 A014907 A014908

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Olivier Gérard

STATUS

approved

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Last modified October 19 13:01 EDT 2019. Contains 328222 sequences. (Running on oeis4.)