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 A071861 Numbers k such that the largest prime factor of k is equal to the sum of primes dividing k+1 (with repetition). 2
 5, 44, 51, 3103, 3145, 3509, 3737, 3887, 4929, 6024, 6344, 9085, 10286, 10787, 11725, 12035, 13052, 14314, 14816, 14839, 19071, 19662, 20513, 23779, 27950, 28248, 35860, 36239, 41005, 45135, 48447, 50826, 52124, 53416, 59186, 64355 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 EXAMPLE 3145 is a term because 3145 = 5*17*37 and sopfr(3146) = 2+11+11+13 = 37. MATHEMATICA seq = {}; gpfPrev = 0; Do[sopfr = Plus @@ Times @@@ (f = FactorInteger[n]); If[sopfr == gpfPrev, AppendTo[seq, n - 1]]; gpfPrev = f[[-1, 1]], {n, 2, 65000}]; seq (* Amiram Eldar, Dec 08 2019 *) CROSSREFS Cf. A001414, A006530. Sequence in context: A030698 A080284 A193458 * A159298 A262118 A173376 Adjacent sequences: A071858 A071859 A071860 * A071862 A071863 A071864 KEYWORD nonn AUTHOR Jason Earls, Jun 09 2002 EXTENSIONS Offset corrected by Amiram Eldar, Dec 08 2019 STATUS approved

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Last modified May 17 23:39 EDT 2024. Contains 372608 sequences. (Running on oeis4.)