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A133683
Linear recurrence a(n) = a(n-3) + 2a(n-5), starting from all-one initial conditions.
0
1, 1, 1, 1, 1, 3, 3, 3, 5, 5, 9, 11, 11, 19, 21, 29, 41, 43, 67, 83, 101, 149, 169, 235, 315, 371, 533, 653, 841, 1163, 1395, 1907, 2469, 3077, 4233, 5259, 6891, 9171, 11413, 15357, 19689, 25195, 33699, 42515, 55909
OFFSET
1,6
FORMULA
O.g.f.: -x*(1+x+x^2)/(-1+x^3+2*x^5) . - R. J. Mathar, Jan 07 2008
EXAMPLE
a(14) = a(11) + 2a(9) = 9 + 2*5 = 19
MATHEMATICA
LinearRecurrence[{0, 0, 1, 0, 2}, {1, 1, 1, 1, 1}, 50] (* Harvey P. Dale, Jan 16 2012 *)
PROG
(PARI) a(n)=([0, 1, 0, 0, 0; 0, 0, 1, 0, 0; 0, 0, 0, 1, 0; 0, 0, 0, 0, 1; 2, 0, 1, 0, 0]^(n-1)*[1; 1; 1; 1; 1])[1, 1] \\ Charles R Greathouse IV, Oct 03 2016
CROSSREFS
Sequence in context: A046702 A357057 A226592 * A182998 A117900 A318203
KEYWORD
easy,nonn
AUTHOR
David Eppstein, Jan 04 2008
STATUS
approved