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A076170
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Triangular numbers whose largest proper divisor is also triangular.
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1
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1, 3, 6, 45, 210, 7140, 122265, 242556, 1702935, 8239770, 279909630, 4601330415, 9508687656, 64088265153, 323015470680, 10973017315470, 173166468725253, 372759573255306, 2411897769074475, 12662852473364940, 430164224521152660, 6516946879404850395
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OFFSET
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1,2
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COMMENTS
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LINKS
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PROG
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(PARI) isTriang(n) = local(x); x = sqrtint(2*n); n == x*(x + 1)/2;
i = 1; n = 1; print1(n, ", "); while(1, i++; n += i; f = factor(n); if (isTriang(n/f[1, 1]), print1(n, ", "))); \\ David Wasserman, Apr 05 2005
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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