A093051 Exponent of 2 in (3^n-3)*2^n.

0, 1, 4, 3, 7, 5, 8, 7, 12, 9, 12, 11, 15, 13, 16, 15, 21, 17, 20, 19, 23, 21, 24, 23, 28, 25, 28, 27, 31, 29, 32, 31, 38, 33, 36, 35, 39, 37, 40, 39, 44, 41, 44, 43, 47, 45, 48, 47, 53, 49, 52, 51, 55, 53, 56, 55, 60, 57, 60, 59, 63, 61, 64, 63, 71, 65, 68, 67, 71

Offset: 0

Author

Ralf Stephan, Mar 16 2004

Keywords

• nonn

Crossrefs

a(n) is the exponent of 2 in A009613(n), A010043(n), A010046(n), A012388(n-1), A009518(n), A012391(n-1), A012457(n-1), A012458(n-1), A012461(n-1), A012462(n-2).

Cf. A093050, A093052, A090740.

Programs

PARI

a(n)=if(n<1,0,if(n%2==0,a(n/2)+2*floor((n+2)/4)+1,n))

Formula

Recurrence: a(2n) = a(n) + [(n+1)/2] + 1, a(2n+1) = 2n+1.

a(n) = A090740(n) + n - 1, for n >= 1. - Amiram Eldar, Sep 14 2024