A178774 a(2n) = 3*a(n), a(2n+1) = a(n) + a(n-1), with a(0)=a(1)=1.

1, 1, 3, 2, 9, 4, 6, 5, 27, 11, 12, 13, 18, 10, 15, 11, 81, 32, 33, 38, 36, 23, 39, 25, 54, 31, 30, 28, 45, 25, 33, 26, 243, 92, 96, 113, 99, 65, 114, 71, 108, 74, 69, 59, 117, 62, 75, 64, 162, 79, 93, 85, 90, 61, 84, 58, 135, 73, 75, 70, 99, 58, 78, 59, 729, 269, 276, 335, 288

Offset

0,3

Links

R. J. Mathar, Table of n, a(n) for n = 0..1000 replacing earlier file of Greubel, including a(0).

Maple

A178774 := proc(n)
    option remember;
    if n <=1 then
        1;
    elif type(n, even) then
        3*procname(n/2) ;
    else
        procname(floor(n/2))+procname(floor(n/2)-1) ;
    end if;
end proc: # R. J. Mathar, Jun 19 2021

Mathematica

a[0] = a[1] = 1; a[n_] := a[n] = If[ OddQ@n, a[(n - 1)/2] + a[(n - 3)/2], 3*a[n/2]]; Array[a, 70]

Crossrefs

Cf. A178590.

Sequence in context: A090639 A294370 A325984 * A320273 A266636 A182652

Adjacent sequences: A178771 A178772 A178773 * A178775 A178776 A178777

Keyword

nonn,easy

Author

Robert G. Wilson v, Jun 11 2010

Extensions

a(0)=1 prepended by R. J. Mathar, Jun 19 2021

Status

approved