A019462 Add 1, multiply by 1, add 2, multiply by 2, etc., start with 3.

3, 4, 4, 6, 12, 15, 45, 49, 196, 201, 1005, 1011, 6066, 6073, 42511, 42519, 340152, 340161, 3061449, 3061459, 30614590, 30614601, 336760611, 336760623, 4041127476, 4041127489, 52534657357, 52534657371, 735485203194, 735485203209, 11032278048135, 11032278048151

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Links

• Paolo Xausa, Table of n, a(n) for n = 0..800
• Nick Hobson, Python program for this sequence

Crossrefs

Cf. A019461 (same, but start with 0), A019463 (start with 1), A019460 (start with 2), A082448 (start with 4).

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

Programs

Mathematica

Module[{a = 3}, Flatten[{a, Array[{a += #, a *= #} &, 20]}]] (* Paolo Xausa, Oct 24 2024 *)

PARI

A019462(n, a=3)={for(i=2, n+1, if(bittest(i, 0), a*=i\2, a+=i\2)); a} \\ M. F. Hasler, Feb 25 2018

Extensions

Edited by M. F. Hasler, Feb 25 2018