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A038340 Second line of 5-wave sequence A038201. 0
1, 4, 9, 50, 105, 616, 1287, 7601, 15873, 93819, 195910, 1158052, 2418195, 14294449, 29849041, 176444054, 368442700, 2177943781, 4547886208, 26883530748, 56137003923, 331837870408, 692929213991, 4096053203771, 8553197751125 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..24.

F. v. Lamoen, Wave sequences

Index to sequences with linear recurrences with constant coefficients, signature (0,15,0,-35,0,28,0,-9,0,1).

FORMULA

G.f.: (x^7+x^6-6*x^5-5*x^4+10*x^3+6*x^2-4*x-1) / (x^10-9*x^8+28*x^6-35*x^4+15*x^2-1). [From Alois P. Heinz, Jul 16 2009]

MAPLE

a:= n-> (Matrix ([`if` (irem(n, 2)=0, [9, 1, 0, -1, -4], [4, 0, -1, -3, -9])]). Matrix(5, (i, j)-> if i=j-1 then 1 elif j=1 then [15, -35, 28, -9, 1][i] else 0 fi) ^iquo(n+1, 2))[1, 2]: seq (a(n), n=0..24); [From Alois P. Heinz, Jul 16 2009]

CROSSREFS

Sequence in context: A053925 A053943 A053955 * A016489 A030694 A060998

Adjacent sequences:  A038337 A038338 A038339 * A038341 A038342 A038343

KEYWORD

nonn,easy

AUTHOR

Floor van Lamoen (fvlamoen(AT)hotmail.com)

STATUS

approved

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Last modified December 18 18:44 EST 2014. Contains 252174 sequences.