OFFSET

1,1

COMMENTS

A version of A318965.

If a term t is divisible by a prime power p^k, then p must appear at least k times in the decimal representation of t. The copies of p are allowed to overlap; however, in the first 12 terms of the sequence, this does not occur, and only a(2), a(4), and a(9) are nonsquarefree.

EXAMPLE

a(2) = 119911 = 11 * 11 * 991.

a(3) = 2510 = 2 * 5 * 251.

a(4) = 21372 = 2 * 2 * 3 * 13 * 137.

a(5) = 1943795 = 5 * 7 * 19 * 37 * 79.

a(6) = 73171842 = 2 * 3 * 17 * 31 * 73 * 317.

a(7) = 113678565 = 3 * 5 * 7 * 11 * 13 * 67 * 113.

CROSSREFS

KEYWORD

nonn,base,more

AUTHOR

Altug Alkan, Sep 08 2018

EXTENSIONS

Terms computed by Giovanni Resta, Sep 08 2018

STATUS

approved