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Search: id:A093722
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| A093722 |
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Integers of the form (n^2-1)/120. |
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+0
3
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| 0, 1, 3, 7, 8, 14, 20, 29, 31, 42, 52, 66, 69, 85, 99, 118, 122, 143, 161, 185, 190, 216, 238, 267, 273, 304, 330, 364, 371, 407, 437, 476, 484, 525, 559, 603, 612, 658, 696, 745, 755, 806, 848, 902, 913, 969, 1015, 1074, 1086, 1147, 1197, 1261, 1274, 1340
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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This is "one-fifteenth of triangular numbers (integers only)" [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Mar 04 2009]
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LINKS
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Harry J. Smith, Table of n, a(n) for n=0,...,20000
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FORMULA
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a(-1-n)=a(n).
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MATHEMATICA
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lst={}; s=0; Do[s+=n/15; If[Floor[s]==s, AppendTo[lst, s]], {n, 0, 7!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Mar 04 2009]
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PROGRAM
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(PARI) {a(n)= (((n\4*3 +n%4)*10+ (-1)^(n\2))^2 -1)/120 } /* Michael Somos Oct 17 2006 */
(PARI) { for (n=0, 20000, a=(((n\4*3 + n%4)*10 + (-1)^(n\2))^2 - 1)/120; write("b093722.txt", n, " ", a); ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jun 18 2009]
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CROSSREFS
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Cf. A002381.
Cf. a(n)=(A057538(n)^2-1)/120.
Sequence in context: A106474 A127441 A067064 this_sequence A002381 A131559 A051211
Adjacent sequences: A093719 A093720 A093721 this_sequence A093723 A093724 A093725
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KEYWORD
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nonn
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AUTHOR
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Michael Somos, Apr 13 2004
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