A038340 Second line of 5-wave sequence A038201.

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

Offset

0,2

Links

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

F. v. Lamoen, Wave sequences

Index entries for 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). - 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); # 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

Status

approved