Voozh

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

(list; graph; refs; listen; history; text; internal format)

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

URL: https://oeis.org/A181412

⇱ A181412 - OEIS