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A175396
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Numbers whose sum of squares of digits is a square.
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7
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 34, 40, 43, 50, 60, 68, 70, 80, 86, 90, 100, 122, 148, 184, 200, 212, 221, 236, 244, 263, 269, 296, 300, 304, 326, 340, 362, 366, 400, 403, 418, 424, 430, 442, 447, 474, 481, 488, 500, 600, 608, 623, 629, 632, 636, 663
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OFFSET
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1,3
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COMMENTS
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Previous name: Numbers n such that Sum_{i=1..r, x(i)^2} is a perfect square, where x(i) = digits of n. r=1+floor(log_10 n).
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LINKS
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EXAMPLE
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34 is a term: 3^2 + 4^2 = 25 = 5^2.
122 is a term: 1^2 + 2^2 + 2^2 = 9 = 3^2.
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MATHEMATICA
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Select[Range[0, 666], IntegerQ[Sqrt[Plus @@ (IntegerDigits[#]^2)]] &] (* Ivan Neretin, Aug 03 2015 *)
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PROG
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(PARI) isok(n) = {digs = Vec(Str(n)); issquare(sum(i=1, #digs, eval(digs[i])^2))} \\ Michel Marcus, Jun 02 2013
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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EXTENSIONS
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Corrected and extended by Neven Juric, Jul 12 2010
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STATUS
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approved
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