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A074238
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Numbers n such that the sum of the reverses of 1,2,...,n is a perfect square.
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0
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1, 8, 26, 53, 3087, 6173, 8091, 12330, 18358, 42898, 294847, 27382381, 49290155, 426131190, 1350661780, 3161620702, 4461944219, 17625479383, 40766706170, 61554358125, 270930998357
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OFFSET
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1,2
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COMMENTS
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LINKS
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EXAMPLE
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reverse(1) + reverse(2) + ... + reverse(25) + reverse(26) = 1 + 2 + ...+ 52 + 62 = 729 = 27^2, so 26 is a term of the sequence.
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MATHEMATICA
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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
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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