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A087454
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Multiplicative inverse of the n-th prime prime(n) modulo prime(n-1).
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2
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1, 2, 3, 2, 6, 10, 9, 5, 4, 15, 26, 28, 21, 11, 8, 9, 30, 51, 17, 36, 61, 20, 14, 78, 73, 51, 26, 54, 82, 105, 32, 22, 69, 14, 75, 126, 131, 41, 28, 29, 90, 163, 96, 145, 99, 83, 88, 56, 114, 172, 39, 120, 217, 42, 43, 44, 135, 226, 208, 141, 85, 21, 77, 156, 235, 68, 276
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OFFSET
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2,2
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LINKS
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EXAMPLE
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We have a(7) = 10 because prime(7)*10 = 170 = 1 [mod 13] = 1 [mod prime(6)].
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MAPLE
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seq(`mod`(1/ithprime(n), ithprime(n-1)), n = 2..70); # G. C. Greubel, Aug 09 2019
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MATHEMATICA
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Table[PowerMod[Prime[n], -1, Prime[n - 1]], {n, 2, 68}] (* Geoffrey Critzer, May 16 2015 *)
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PROG
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(Magma) [InverseMod(NthPrime(n), NthPrime(n-1)): n in [2..70]]; // G. C. Greubel, Aug 09 2019
(Sage) [nth_prime(n).inverse_mod(nth_prime(n-1)) for n in (2..70)] # G. C. Greubel, Aug 09 2019
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CROSSREFS
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KEYWORD
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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