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Search: id:A129196
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| A129196 |
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a(n)=denominator(3(3+(-1)^n)/(n+1)^3);. |
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+0
5
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| 1, 4, 9, 32, 125, 36, 343, 256, 243, 500, 1331, 288, 2197, 1372, 1125, 2048, 4913, 972, 6859, 4000, 3087, 5324, 12167, 2304, 15625, 8788, 6561, 10976, 24389, 4500, 29791, 16384, 11979, 19652, 42875, 7776
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Numerator of 3(3+(-1)^n)/(n+1)^3 is A129197.
(1/(2*pi))*int(exp(i*(n+1)*t)((t-pi)/i)^3,t,0,2*pi))=(A129202(n)*pi^2-A129203(n))/A129196(n), i=sqrt(-1).
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FORMULA
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a(n)=A129204(n+1)/(5/3+(4/3)*cos(2*pi*(n+1)/3));
a(n)=denominator((1/(2*pi))*int(exp(i*(n+1)*t)((t-pi)/i)^3,t,0,2*pi)), i=sqrt(-1);
a(n)=denominator((pi^2*(n+1)^2-6)/(n+1)^3);
a(n)=((n+1)^3/(gcd(n+1,2)*gcd(n+1,3))); - Paul Barry (pbarry(AT)wit.ie), Oct 09 2007
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CROSSREFS
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Sequence in context: A149119 A149120 A057819 this_sequence A119574 A006393 A076966
Adjacent sequences: A129193 A129194 A129195 this_sequence A129197 A129198 A129199
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KEYWORD
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easy,frac,nonn
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Apr 02 2007, Apr 03 2007
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