

A179889


Triangular numbers whose reverse is a square (possibly with fewer digits).


6



1, 10, 630, 52650, 165600, 986310, 9446031, 9485190, 10693000, 1270004401, 14214075921, 140884670790, 1809702709101, 4614899724711, 6766532724546, 9802814901400, 10210140486640, 14287075542460, 52657436563056, 98855178542676
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OFFSET

1,2


LINKS

Giovanni Resta, Table of n, a(n) for n = 1..36 (terms < 2*10^24)


EXAMPLE

9446031 is triangular and 1306449 is a square.


MATHEMATICA

trnos=Accumulate[Range[14070000]];
sqnoQ[n_]:=IntegerQ[Sqrt[FromDigits[Reverse[IntegerDigits[n]]]]]
Select[trnos, sqnoQ] (* Harvey P. Dale, Jan 31 2011 *)


CROSSREFS

A variant of A066703. Cf. A069673, A181412, A066528.
Sequence in context: A308145 A159622 A115692 * A209472 A132543 A261328
Adjacent sequences: A179886 A179887 A179888 * A179890 A179891 A179892


KEYWORD

base,nonn


AUTHOR

Harvey P. Dale, Jan 30 2011


EXTENSIONS

More terms from Harvey P. Dale, Jan 31 2011


STATUS

approved



