A131588 Interlaces A007583 with A083420.

1, 1, 3, 7, 11, 31, 43, 127, 171, 511, 683, 2047, 2731, 8191, 10923, 32767, 43691, 131071, 174763, 524287, 699051, 2097151, 2796203, 8388607, 11184811, 33554431, 44739243, 134217727, 178956971, 536870911, 715827883, 2147483647, 2863311531

Offset: 0

Author

Creighton Dement, Aug 30 2007

Keywords

• easy
• nonn

Comments

Floretion Algebra Multiplication Program, FAMP Code: minseq[A*B] with A = + .25'i + .25i' + .25'ii' + .25'jj' + .25'kk' + .25'jk' + .25'kj' + .25e and B = + 'i + 'j - 2'k (apart from initial term and signs)

Links

• Index entries for linear recurrences with constant coefficients, signature (0,5,0,-4).

Crossrefs

Cf. A007583, A083420, A001045.

Formula

a(n) = 5*a(n-2) - 4*a(n-4); a(n) = (5*2^n+(-2)^n-8*(-1)^n-4)/12; g.f. (1+x-2*x^2+2*x^3)/((x-1)*(2*x+1)*(2*x-1)*(x+1))