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A051930 Number of independent sets of vertices in graph K_5 X C_n (n > 2). 1
6, 1, 31, 136, 731, 3771, 19606, 101781, 528531, 2744416, 14250631, 73997551, 384238406, 1995189561, 10360186231, 53796120696, 279340789731, 1450500069331, 7531841136406, 39109705751341, 203080369893131 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index to sequences with linear recurrences with constant coefficients, signature (4,6,1).

FORMULA

a(n) = 4*a(n-1) + 6*a(n-2) + a(n-3).

G.f.: (6-23*x-9*x^2)/((1+x)*(1-5*x-x^2)). [Colin Barker, May 22 2012]

MATHEMATICA

LinearRecurrence[{4, 6, 1}, {6, 1, 31}, 30] (* Vincenzo Librandi, Jun 17 2012 *)

PROG

(MAGMA) I:=[6, 1, 31]; [n le 3 select I[n] else 4*Self(n-1)+6*Self(n-2)+Self(n-3): n in [1..30]]; // Vincenzo Librandi, Jun 17 2012

CROSSREFS

Sequence in context: A030524 A241171 A245576 * A147320 A038255 A075501

Adjacent sequences:  A051927 A051928 A051929 * A051931 A051932 A051933

KEYWORD

easy,nonn

AUTHOR

Stephen G. Penrice (spenrice(AT)ets.org), Dec 19 1999

EXTENSIONS

More terms from James A. Sellers, Dec 20 1999

STATUS

approved

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Last modified November 22 12:35 EST 2014. Contains 249805 sequences.