A291555 Number of even numbers less than 10^n that contain their greatest odd factor as a substring.

0, 1, 4, 15, 40, 57, 76, 108, 146, 194, 258, 336, 447, 544, 663, 807, 970, 1132, 1333, 1567

Offset: 1

Author

Bobby Jacobs and Robert G. Wilson v, Aug 26 2017

Keywords

• nonn
• base
• more

Comments

The number of terms of A291460 less than 10^n.

2^10*x = 1024*x contains x for all x from 1 to 41. Therefore, most of the terms in A291460 less than 10^5 are of the form 1024*x for odd x from 1 to 41.

Examples

			There are 4 numbers in A291460 less than 10^3 = 1000 (16, 128, 384, 512). Therefore, a(3) = 4.
		

Crossrefs

Cf. A000265, A291460.

Extensions

a(14)-a(20) from Giovanni Resta, Aug 31 2017