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 A085753 Least k such that n^n + k is a semiprime. 3
 3, 0, 6, 3, 2, 5, 6, 3, 4, 3, 6, 31, 6, 3, 4, 1, 20, 19, 28, 3, 8, 3, 60, 5, 16, 15, 46, 3, 2, 7, 12, 13, 4, 3, 18, 3, 9, 3, 32, 7, 6, 37, 30, 61, 2, 81, 26, 5, 34, 79, 62, 27, 44, 5, 16, 15, 10, 133, 12, 31, 28, 49, 26, 21, 92, 43, 76, 67, 38, 57, 36, 43, 24, 115, 2, 25, 74, 179, 28, 27, 52, 15 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The parity of a(n) is opposite to that of n. LINKS Dario Alejandro Alpern, Factorization using the Elliptic Curve Method MATHEMATICA PrimeFactorExponentsAdded[n_] := Plus @@ Flatten[ Table[ # [[2]], {1}] & /@ FactorInteger[n]]; f[n_] := Block[{k = 0}, While[ PrimeFactorExponentsAdded[n^n + k] != 2, k++ ]; k]; Table[ f[n], {n, 1, 40}] CROSSREFS Cf. A089542, A089543, A089544. Sequence in context: A259659 A005889 A095712 * A120008 A162197 A160770 Adjacent sequences:  A085750 A085751 A085752 * A085754 A085755 A085756 KEYWORD nonn AUTHOR Jason Earls, Jul 21 2003 EXTENSIONS Edited and extended by Robert G. Wilson v, Aug 14 2003 Corrected and extended by Ray Chandler, Nov 22 2003 a(69)-a(82) from Max Alekseyev, Jun 13 2009 STATUS approved

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Last modified October 15 10:15 EDT 2019. Contains 328026 sequences. (Running on oeis4.)