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A032126 "BIK" (reversible, indistinct, unlabeled) transform of 1,2,3,4... 1
1, 3, 6, 15, 33, 84, 203, 525, 1330, 3465, 8955, 23400, 60957, 159471, 416702, 1090635, 2853229, 7469052, 19548759, 51177225, 133969386, 350730933, 918187991, 2403833040, 6293218393, 16475822139, 43134005238 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

C. G. Bower, Transforms (2)

Index entries for linear recurrences with constant coefficients, signature (3,2,-9,2,3,-1).

FORMULA

a(2n+1) = 1/2 * [F(4n+1) + F(4n) + F(2n+2) + F(2n)], with F(n) = A000045(n). - Ralf Stephan, May 04 2004

Empirical G.f.: x*(x^4-5*x^2+1) / ((x^2-3*x+1)*(x^2-x-1)*(x^2+x-1)). - Colin Barker, Dec 15 2012

MATHEMATICA

LinearRecurrence[{3, 2, -9, 2, 3, -1}, {1, 3, 6, 15, 33, 84}, 30] (* Harvey P. Dale, Dec 14 2016 *)

CROSSREFS

Sequence in context: A000599 A063832 A006647 * A190525 A032176 A173992

Adjacent sequences:  A032123 A032124 A032125 * A032127 A032128 A032129

KEYWORD

nonn

AUTHOR

Christian G. Bower

STATUS

approved

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Last modified February 23 09:23 EST 2018. Contains 299503 sequences. (Running on oeis4.)