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Search: id:A116476
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| A116476 |
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Numbers n such that T(n) + T(n+1) + ... + T(n+10) is a square. |
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1
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| 13, 46, 229, 1608, 7335, 20304, 92391, 635710, 2892133, 8001886, 36403981, 250470288, 1139495223, 3152724936, 14343078279, 98684659918
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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T(n) (or Tn) is the n-th triangular number. - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Mar 30 2006
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EXAMPLE
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T13 + T14 + T15 + T16 + T17 + T18 + T19 + T20 + T21 + T22 + T23 = 91 + 105 + 120 + 136 + 153 + 171 + 190 + 210 + 231 + 253 + 276 = 1936 = 44^2.
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MATHEMATICA
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For[n = 1, n < 100000, n++, If[IntegerQ[Sqrt[Sum[i*(i+1)/2, {i, n, n + 10}]]], Print[n]]] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Mar 30 2006
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CROSSREFS
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Sequence in context: A010003 A007587 A034462 this_sequence A035340 A127305 A001662
Adjacent sequences: A116473 A116474 A116475 this_sequence A116477 A116478 A116479
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KEYWORD
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nonn
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AUTHOR
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Edward Fedorovich (chipramy(AT)012.net.il), Mar 29 2006
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