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

1,3

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.

Links

Table of n, a(n) for n=1..20.

Example

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

Crossrefs

Cf. A000265, A291460.

Sequence in context: A014629 A062486 A193226 * A336995 A053698 A162867

Adjacent sequences: A291552 A291553 A291554 * A291556 A291557 A291558

Keyword

nonn,base,more

Author

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

Extensions

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

Status

approved