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A119037
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Triangular numbers composed of digits {0,1,4}.
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2
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1, 10, 10011, 10440, 41041, 41001040, 141044410, 1010004040, 4104044101, 14041444410, 114011410040100, 440404440401100, 1041401040044401, 40114114410110140, 14001400401400441011, 1040410404040110411004140, 1014411414040144040404100100
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OFFSET
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1,2
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LINKS
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FORMULA
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MATHEMATICA
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Rest[Select[FromDigits/@Tuples[{0, 1, 4}, 12], IntegerQ[(Sqrt[8 # + 1] - 1)/2] &]] (* Vincenzo Librandi, Dec 18 2015 *)
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PROG
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(Magma) [t: n in [1..2*10^7] | Set(Intseq(t)) subset {0, 1, 4} where t is n*(n+1) div 2]; // Vincenzo Librandi, Dec 18 2015
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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