A019466 Multiply by 1, add 1, multiply by 2, add 2, etc.; start with 3.

3, 3, 4, 8, 10, 30, 33, 132, 136, 680, 685, 4110, 4116, 28812, 28819, 230552, 230560, 2075040, 2075049, 20750490, 20750500, 228255500, 228255511, 2739066132, 2739066144, 35607859872, 35607859885, 498510038390, 498510038404, 7477650576060, 7477650576075, 119642409217200

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

Links

• Paolo Xausa, Table of n, a(n) for n = 0..800

Crossrefs

Cf. A082458 (same, but start with 0), A019464 (start with 1), A019465 (start with 2).

Cf. A019460 .. A019463 & A082448 (similar, but first add, then multiply).

Programs

Mathematica

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

PARI

A019466(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