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A093722
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Integers of the form (n^2 - 1) / 120.
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10
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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
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OFFSET
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1,3
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COMMENTS
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LINKS
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FORMULA
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|A113430(n-1)| is the characteristic function of the numbers in A093722.
a(-1 - n) = a(n). a(n) = (A057538(n) * 2 - 1) / 120.
G.f. -x^2*(1+2*x+4*x^2+x^3+4*x^4+x^6+2*x^5) / ( (1+x)^2*(x^2+1)^2*(x-1)^3 ). - R. J. Mathar, Jun 09 2013
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MATHEMATICA
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Select[Table[(n^2-1)/120, {n, 0, 700}], IntegerQ] (* Harvey P. Dale, Nov 26 2010 *)
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PROG
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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, 19999, a=(((n\4*3 + n%4)*10 + (-1)^(n\2))^2 - 1)/120; write("b093722.txt", n+1, " ", a); ) } \\ Harry J. Smith, Jun 18 2009
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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