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A113799 Numbers n such that the n-th triangular number plus the reverse of n gives a square. 0
3, 36, 45, 423, 486, 558, 1377, 6690, 15540, 59460, 110694, 16867050, 443820753 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..13.

EXAMPLE

T(423)+324=300^2.

MATHEMATICA

testQ[n_] := IntegerQ[Sqrt[n(n+1)/2 + FromDigits@Reverse@IntegerDigits@n]]; lst = Select[Range[10^5], testQ]

CROSSREFS

Sequence in context: A158301 A105758 A214852 * A072682 A158207 A227032

Adjacent sequences:  A113796 A113797 A113798 * A113800 A113801 A113802

KEYWORD

base,nonn

AUTHOR

Giovanni Resta, Jan 22 2006

STATUS

approved

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Last modified May 10 21:08 EDT 2021. Contains 343780 sequences. (Running on oeis4.)