A074238 Numbers k such that the sum of the reverses of 1,2,...,k is a perfect square.
1, 8, 26, 53, 3087, 6173, 8091, 12330, 18358, 42898, 294847, 27382381, 49290155, 426131190, 1350661780, 3161620702, 4461944219, 17625479383, 40766706170, 61554358125, 270930998357
Offset: 1
Examples
reverse(1) + reverse(2) + ... + reverse(25) + reverse(26) = 1 + 2 + ...+ 52 + 62 = 729 = 27^2, so 26 is a term of the sequence.
Crossrefs
Cf. A062918.
Programs
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Mathematica
s = 0; r = {}; For[i = 1, i <= 10^5, i++, s = s + FromDigits[Reverse[IntegerDigits[i]]]; If[IntegerQ[s^(1/2)], r = Append[r, i]]]; r
Extensions
a(11)-a(21) from Giovanni Resta, Apr 16 2017
Comments