A111570 a(n) = a(n-1) + a(n-3) + a(n-4), n >= 4, with initial terms 2,5,4,7.

2, 5, 4, 7, 14, 23, 34, 55, 92, 149, 238, 385, 626, 1013, 1636, 2647, 4286, 6935, 11218, 18151, 29372, 47525, 76894, 124417, 201314, 325733, 527044, 852775, 1379822, 2232599, 3612418, 5845015, 9457436, 15302453, 24759886

Offset: 0

Author

Creighton Dement, Aug 10 2005

Keywords

• easy
• nonn

Comments

See comment and FAMP code for A111569.

Floretion Algebra Multiplication Program, FAMP Code: 1vesseq[B+H] with B = - .25'i + .25'j - .25i' + .25j' + k' - .5'kk' - .25'ik' - .25'jk' - .25'ki' - .25'kj' - .5e and H = + .75'ii' + .75'jj' + .75'kk' + .75e

Links

• Index entries for linear recurrences with constant coefficients, signature (1, 0, 1, 1).

Crossrefs

Cf. A001638, A111569, A111571, A111572, A111573, A007598, A000045.

Formula

G.f.: (-2-3*x+x^2-x^3)/((1+x^2)*(x^2+x-1)).

Extensions

Name clarified by Robert C. Lyons, Feb 06 2025