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A087754
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a(n) = (C(2p,p)-2) / p^3, where p = prime(n).
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5
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2, 10, 530, 4734, 474986, 5153122, 676701794, 1232820800342, 15623119507746, 34472401720246110, 6163354867874693078, 83483882991733501114, 15658391111267929558466, 42132263940113324754864134
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OFFSET
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3,1
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LINKS
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R. R. Aidagulov, M. A. Alekseyev. On p-adic approximation of sums of binomial coefficients. Journal of Mathematical Sciences 233:5 (2018), 626-634. doi:10.1007/s10958-018-3948-0 arXiv:1602.02632
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FORMULA
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EXAMPLE
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a(6)=4734 since 13 is the sixth prime and (C(26,13)-2)/13^3 = (10400600-2)/2197 = 4734.
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MATHEMATICA
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Table[(Binomial[2p, p]-2)/p^3, {p, Prime[Range[3, 20]]}] (* Harvey P. Dale, Oct 23 2017 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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