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Search: id:A074238
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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
1
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OFFSET
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1,2
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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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Cf. A062918.
Sequence in context: A122854 A138502 A126176 this_sequence A126264 A085690 A005897
Adjacent sequences: A074235 A074236 A074237 this_sequence A074239 A074240 A074241
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KEYWORD
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base,nonn
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Sep 19 2002
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