A048412 a(n)^2 is a square whose consecutive digits differ by 1.

0, 1, 2, 3, 11, 26, 111, 1111, 11111, 111111, 1111111, 11111111, 111111111

Offset

1,3

Comments

a(14), if it exists, is > 10^17. - Lars Blomberg, Nov 25 2016

Links

Table of n, a(n) for n=1..13.

Formula

a(n) = sqrt(A048411(n)).

Crossrefs

Cf. A002477, A048411.

Sequence in context: A248161 A056851 A284046 * A259428 A002981 A294637

Adjacent sequences: A048409 A048410 A048411 * A048413 A048414 A048415

Keyword

nonn,base,more

Author

Patrick De Geest, Apr 15 1999

Extensions

Offset changed to 1 by Jinyuan Wang, Sep 04 2021

Status

approved