A132418 Sequence is identical to its third differences in absolute values: a(n+k)=3a(n+k-1)-3a(n+k-2)+2a(n+k-3), k=0, 1, 2, 3, 4, a(n+5)=3a(n+4)-3a(n+3), n > 2.

1, 2, 3, 5, 10, 21, 43, 86, 129, 215, 430, 903, 1849, 3698, 5547, 9245, 18490, 38829, 79507

Offset

0,2

Comments

(6n+1)-th terms: 43, 43^2, 43^3, 43^4?

Links

Table of n, a(n) for n=0..18.

Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 43).

Formula

6n-th terms of a(n) opposite to the 6th of third differences. These terms are 21=3*7, 903=21*43, 38829=21*43^2.

Mathematica

LinearRecurrence[{0, 0, 0, 0, 0, 43}, {1, 2, 3, 5, 10, 21}, 19] (* Ray Chandler, Sep 23 2015 *)

Crossrefs

Sequence in context: A125312 A300550 A014626 * A024494 A131708 A002991

Adjacent sequences: A132415 A132416 A132417 * A132419 A132420 A132421

Keyword

nonn

Author

Paul Curtz, Nov 13 2007

Status

approved