A053903 Squares composed of digits {1,5,6}.

1, 16, 1156, 6561, 111556, 556516, 6661561, 11115556, 165611161, 1111155556, 1566655561, 6661661161, 111111555556, 1551155666116, 1561665111556, 11111115555556, 156166661115556, 1111111155555556, 111111111555555556, 5115511551651111556, 11111111115555555556

Offset: 1

Author

Patrick De Geest, Mar 15 2000

Keywords

• nonn
• base

Comments

Includes all numbers of the form ((10^k-1)/3 + 1)^2. - Andrew Howroyd, Oct 18 2024

Links

• Zhao Hui Du, Table of n, a(n) for n = 1..55
• Patrick De Geest, Squares containing at most three distinct digits, Index entries for related sequences

Crossrefs

Cf. A053902.

Formula

a(n) = A053902(n)^2. - Andrew Howroyd, Oct 18 2024