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Search: id:A130111
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| A130111 |
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Rearrangement of natural numbers such that each five terms sum up to a perfect square. |
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+0
4
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| 1, 2, 3, 4, 6, 5, 7, 8, 9, 20, 10, 11, 12, 13, 18, 14, 15, 16, 17, 19, 21, 22, 23, 24, 31, 25, 26, 27, 28, 38, 29, 30, 32, 33, 45, 34, 35, 36, 37, 54, 39, 40, 41, 42, 63, 43, 44, 46, 47, 76, 48, 49, 50, 51, 58, 52, 53, 55, 56, 73, 57, 59, 60, 61, 87, 62, 64, 65, 66, 67, 68, 69
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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1+2+3+4+6=16, 5+7+8+9+20=49, 10+11+12+13+18=64, 14+15+16+17+19=81.
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MATHEMATICA
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s={}; ra=Range[1000]; Do[su=ra[[1]]+ra[[2]]+ra[[3]]+ra[[4]]; c=5; While[ !IntegerQ[Sqrt[su+ra[[c]]]], c++ ]; rac=ra[[c]]; s=Join[s, {ra[[1]], ra[[2]], ra[[3]], ra[[4]], rac}]; ra=Complement[ra, {ra[[1]], ra[[2]], ra[[3]], ra[[4]], rac}], {50}]; s
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CROSSREFS
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Cf. A130108, A130109, A130110.
Adjacent sequences: A130108 A130109 A130110 this_sequence A130112 A130113 A130114
Sequence in context: A057508 A057164 A085175 this_sequence A104182 A080541 A072759
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov (zakseidov(AT)yahoo.com), May 08 2007
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