A129094 a(n) = A030067(2^n + 2^(n-1) - 1) for n>=1, where A030067 gives the semi-Fibonacci numbers.

1, 3, 9, 35, 189, 1523, 19409, 407067, 14448821, 886912635, 95777365753, 18445977557011, 6405629912921517, 4047190499790323395, 4687597187390655089313, 10017007133285072336267467

Offset

1,2

Links

Table of n, a(n) for n=1..16.

Example

This sequence equals the central terms of the triangle formed from the semi-Fibonacci numbers (A030067) with 2^n terms in row n for n>=1:
n=0: 1;
n=1: (1), 2;
n=2: 1, (3), 2, 5;
n=3: 1, 6, 3, (9), 2, 11, 5, 16;
n=4: 1, 17, 6, 23, 3, 26, 9, (35), 2, 37, 11, 48, 5, 53, 16, 69; ...
The semi-Fibonacci numbers (A030067) start:
[1, (1), 2, 1, (3), 2, 5, 1, 6, 3, (9), 2, 11, 5, 16, 1, ...],
and obey the recurrence:
A030067(n) = A030067(n/2) when n is even; and
A030067(n) = A030067(n-1) + A030067(n-2) when n is odd.

Prog

(PARI)

Crossrefs

Cf. A030067; A129092, A129093.

Sequence in context: A155858 A000834 A005346 * A059424 A354239 A002575

Adjacent sequences: A129091 A129092 A129093 * A129095 A129096 A129097

Keyword

nonn

Author

Paul D. Hanna, Mar 29 2007

Status

approved