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Search: id:A120268
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| A120268 |
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Numerator of Sum[1/(2k-1)^2,{k,1,n}]. |
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+0
2
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| 1, 10, 259, 12916, 117469, 14312974, 2430898831, 487983368, 141433003757, 51174593563322, 51270597630767, 27164483940418988, 3400039831130408821, 30634921277843705014, 25789165074168004597399
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OFFSET
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1,2
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COMMENT
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a((p-1)/2) is divisible by prime p>3.
Denominators are A128492.
The limit of the rationals r(n):=Sum[1/(2k-1)^2,{k,1,n}] for n->infinity is (Pi^2)/8 = (1-1/2^2)*Zeta(2) which is approximately 1.233700550.
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LINKS
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W. Lang, Rationals and limit. .
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FORMULA
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a(n) = numerator[Sum[1/(2k-1)^2,{k,1,n}]].
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MATHEMATICA
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Numerator[Table[Sum[1/(2k-1)^2, {k, 1, n}], {n, 1, 25}]]
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CROSSREFS
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Cf. A025550, A007406.
Sequence in context: A100743 A126468 A024293 this_sequence A001824 A024294 A084999
Adjacent sequences: A120265 A120266 A120267 this_sequence A120269 A120270 A120271
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KEYWORD
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frac,nonn
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AUTHOR
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Alexander Adamchuk (alex(AT)kolmogorov.com), Jul 01 2006
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