A087276 Write n in binary: 1ab..yz, then a(n) = 1ab..yz + ... + 1yz + 1z + 1.

1, 3, 4, 7, 9, 9, 11, 15, 18, 19, 22, 19, 22, 23, 26, 31, 35, 37, 41, 39, 43, 45, 49, 39, 43, 45, 49, 47, 51, 53, 57, 63, 68, 71, 76, 75, 80, 83, 88, 79, 84, 87, 92, 91, 96, 99, 104, 79, 84, 87, 92, 91, 96, 99, 104, 95, 100, 103, 108, 107, 112, 115

Offset: 1

Author

Ralf Stephan, Aug 27 2003

Keywords

• nonn
• easy

Comments

a(n) = A087275(n) + n.

Crossrefs

Cf. A005187, A059893, A059894.

Programs

PARI

a(n)=local(v, s, l); v=binary(n); l=length(v); s=0; for(k=2, l, s=s+2^(l-k)+sum(m=k+1, l, v[m]*2^(l-m))); s+n

Formula

a(1) = 1, a(2n) = 2a(n) + 1, a(2n+1) = 2*a(n) + floor(log_2(n)) + 2.