A181412 Squares whose reverse is a triangular number; trailing zeros are permitted.

1, 100, 10000, 1000000, 1306449, 100000000, 130644900, 1044000721, 10000000000, 12957041241, 13064490000, 104400072100, 1000000000000, 1019072079081, 1174279984164, 1295704124100, 1306449000000, 6454272356676, 10440007210000

Offset

1,2

Comments

Suggested by T. D. Noe.

Links

Giovanni Resta, Table of n, a(n) for n = 1..73 (terms < 10^24)

Example

1306449 is 1143 squared, and its reverse, 9446031, is a triangular number.

Mathematica

trnos = Accumulate[Range[300000]]; Select[Range[210000]^2, MemberQ[trnos, FromDigits[Reverse[IntegerDigits[#]]]] &]

Crossrefs

Cf. A066702, A001110, A066703, A179889, A066528, A069673.

Sequence in context: A029798 A029775 A077440 * A029794 A029801 A098608

Adjacent sequences: A181409 A181410 A181411 * A181413 A181414 A181415

Keyword

nonn,base

Author

Harvey P. Dale, Jan 30 2011

Extensions

a(12)-a(19) from Donovan Johnson, Feb 12 2011

Status

approved