A115059 a(n+4) = a(n+3)+a(n+1)+a(n)+k(n), where k(n) = 0, 1, 0, or -1 according to n mod 4.

0, 0, 1, 1, 1, 3, 5, 6, 10, 19, 30, 45, 74, 124, 199, 317, 515, 839, 1355, 2186, 3540, 5735, 9276, 15001, 24276, 39288, 63565, 102841, 166405, 269259, 435665, 704910, 1140574, 1845499, 2986074, 4831557, 7817630, 12649204, 20466835, 33116021

Offset

0,6

Comments

a(n) + 2a(n+2) + a(n+4) is the (n+4)th Fibonacci number.

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Mathematica

nxt[{n_, a_, b_, c_, d_}]:={n+1, b, c, d, a+b+d+Which[Mod[n+1, 4] == 0, 0, Mod[ n+1, 4] == 1, 1, Mod[n+1, 4]==2, 0, True, -1]}; NestList[nxt, {3, 0, 0, 1, 1}, 40][[All, 2]] (* Harvey P. Dale, Mar 24 2022 *)

Crossrefs

Sequence in context: A194466 A270416 A290269 * A250218 A092835 A335403

Adjacent sequences: A115056 A115057 A115058 * A115060 A115061 A115062

Keyword

nonn

Author

M. N. Deshpande (dpratap_ngp(AT)sancharnet.in), Feb 28 2006

Extensions

Edited by Don Reble, Mar 14 2006

Status

approved