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A066561
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a(n) is the smallest triangular number divisible by n.
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6
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1, 6, 3, 28, 10, 6, 21, 120, 36, 10, 55, 36, 78, 28, 15, 496, 136, 36, 171, 120, 21, 66, 253, 120, 300, 78, 351, 28, 406, 120, 465, 2016, 66, 136, 105, 36, 666, 190, 78, 120, 820, 210, 903, 528, 45, 276, 1081, 528, 1176, 300, 153, 780, 1378, 378, 55, 1176, 171
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OFFSET
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1,2
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COMMENTS
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See A344005 for an efficient algorithm. - N. J. A. Sloane, Jul 13 2021
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LINKS
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T. D. Noe, Table of n, a(n) for n = 1..1000
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FORMULA
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a(n) = A000217(A011772(n)). - Bill McEachen, Dec 28 2021
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PROG
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(PARI) { for (n=1, 1000, s=0; b=0; while (b==0, s++; t=s*(s+1)/2; if (t%n == 0, b=1)); write("b066561.txt", n, " ", t) ) } \\ Harry J. Smith, Mar 05 2010
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CROSSREFS
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Cf. A000217, A011772, A344005, A345988.
Sequence in context: A285607 A287546 A285559 * A073872 A281677 A282303
Adjacent sequences: A066558 A066559 A066560 * A066562 A066563 A066564
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy, Dec 17 2001
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EXTENSIONS
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More terms from Naohiro Nomoto, Dec 26 2001
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STATUS
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approved
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