A066702 Square numbers whose reverse is triangular with the same number of digits.

0, 1, 1306449, 1044000721, 12957041241, 1019072079081, 1174279984164, 6454272356676, 65036563475625, 67624587155889, 123826990849454025, 170448128872993657764, 19198191503444720114404

Offset: 1

Author

Erich Friedman, Jan 14 2002

Keywords

• base
• more
• nonn

Comments

The sequence of corresponding triangular numbers is A066703. - Robert G. Wilson v, Jan 31 2011

Examples

			9446031 is triangular and 1306449 is a square.
		

Crossrefs

Cf. A066703, A181412. - Harvey P. Dale, Jan 30 2011

Programs

Mathematica

lst = {0}; For[i = 1, i > 0, i++, s = i^2; t = FromDigits@ Reverse@ IntegerDigits@ s; If[ IntegerQ@ Sqrt[8 t + 1] && Mod[s, 10] > 0, AppendTo[lst, s]; Print@ lst]]

Extensions

a(12)-a(13) from and offset corrected by Giovanni Resta, Jun 20 2015