A019461 Add 1, multiply by 1, add 2, multiply by 2, etc.; start with 0.

0, 1, 1, 3, 6, 9, 27, 31, 124, 129, 645, 651, 3906, 3913, 27391, 27399, 219192, 219201, 1972809, 1972819, 19728190, 19728201, 217010211, 217010223, 2604122676, 2604122689, 33853594957, 33853594971, 473950329594, 473950329609, 7109254944135, 7109254944151, 113748079106416

Offset

0,4

Links

Seiichi Manyama, Table of n, a(n) for n = 0..899

Nick Hobson, Python program for this sequence

Maple

A019461 := proc(n) option remember; if n = 0 then 0 elif n mod 2 = 1 then (n+1)/2+A019461(n-1) else (n/2)*A019461(n-1); fi; end;

Mathematica

Module[{a = 0}, Join[{a}, Flatten[Array[{a += #, a *= #} &, 20]]]] (* Paolo Xausa, Oct 24 2024 *)

Prog

(PARI) A019461(n, a=0)={for(i=2, n+1, if(bittest(i, 0), a*=i\2, a+=i\2)); a} \\ M. F. Hasler, Feb 25 2018

Crossrefs

Cf. A019463 (same, but start with 1), A019460 (start with 2), A019462 (start with 3), A082448 (start with 4).

Cf. A082458, A019464 .. A019466 (similar, but first multiply, then add).

Sequence in context: A326160 A301536 A296110 * A223556 A067862 A062927

Adjacent sequences: A019458 A019459 A019460 * A019462 A019463 A019464

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Edited by M. F. Hasler, Feb 25 2018

Status

approved