A068538 Nonsquarefree repunits.

111111111, 111111111111111111, 1111111111111111111111, 111111111111111111111111111, 111111111111111111111111111111111111, 111111111111111111111111111111111111111111, 11111111111111111111111111111111111111111111, 111111111111111111111111111111111111111111111

Offset

1,1

Comments

The number of digits of these repunits form the sequence A046412. - Michel Marcus, Nov 24 2013

Links

Table of n, a(n) for n=1..8.

Formula

a(n) = (10^A046412(n) - 1) / 9. - Max Alekseyev, Apr 29 2022

Prog

(PARI) lista(nn) = {for (n=1, nn, if (! issquarefree(r = sum(i=0, n, 10^i)), print1(r, ", ")); ); } \\ Michel Marcus, Nov 24 2013

Crossrefs

Sequence in context: A038451 A202082 A262499 * A186552 A147581 A281448

Adjacent sequences: A068535 A068536 A068537 * A068539 A068540 A068541

Keyword

nonn

Author

Benoit Cloitre, Mar 22 2002

Status

approved