A058444 Squares composed of digits {0,4,9}, not ending with zero.

4, 9, 49, 9409, 44944, 994009, 9909904, 99940009, 404090404, 9999400009, 999994000009, 4004009004004, 9449494444009, 99999940000009, 9999999400000009, 40004000900040004, 999999994000000009, 99999999940000000009, 400004000090000400004, 9999999999400000000009

Offset: 1

Author

Patrick De Geest, Nov 15 2000

Keywords

• nonn
• base

Comments

Includes all numbers of the form (10^k - 3)^2 for k >= 1 and of the form (2*100^k + 10^k + 2)^2 for k >= 1. - Andrew Howroyd, Oct 18 2024

Links

• Zhao Hui Du, Table of n, a(n) for n = 1..54
• Patrick De Geest, Index to related sequences
• Hisanori Mishima, Sporadic tridigital solutions

Crossrefs

Cf. A058443.

Formula

a(n) = A058443(n)^2. - Andrew Howroyd, Oct 18 2024