A176883 Sum of distances of numbers between successive powers of 2 (beginning with 2^1) to previous numbers with same number of prime factors, repetitions included. See example.

1, 6, 19, 55, 151, 359, 849, 1956, 4416, 9861, 21776, 47659, 103501, 223362, 479527, 1024599, 2180237, 4622633, 9769597, 20587721, 43272599, 90739538, 189867698, 396512548, 826579593, 1720267980, 3574753738, 7417943000, 15372756795, 31819255488

Offset

1,2

Links

Table of n, a(n) for n=1..30.

Example

On (2,3,4), between the powers of 2, 3 is one number beyond previous prime 2. So the sum is 1. On (4,5,6,7,8), 5 is 2 beyond 3, 6 is 2 beyond 4, 7 is 2 beyond 5, for a sum of 2+2+2=6. On (8,9,10,11,12, 13,14,15,16), the distances are 3,1,4,4,2,4,1 for a sum of 19. And so on.

Crossrefs

Cf. A176884.

Sequence in context: A127642 A272151 A272562 * A274599 A286184 A027044

Adjacent sequences: A176880 A176881 A176882 * A176884 A176885 A176886

Keyword

nonn

Author

Daniel Tisdale, Apr 27 2010

Extensions

a(5)-a(30) from Ray Chandler, May 05 2010

Status

approved