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 A078581 Arithmetic derivative of the average of n-th twin prime pair. 1
 4, 5, 16, 21, 31, 41, 92, 156, 91, 216, 121, 185, 336, 640, 249, 316, 608, 459, 241, 596, 476, 704, 1296, 493, 627, 619, 1340, 521, 541, 1072, 1647, 691, 1416, 859, 1281, 1624, 1916, 1445, 1257, 1696, 4800, 1301, 1509, 1363, 1313, 2804, 2192, 2200, 1427 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Amiram Eldar, Table of n, a(n) for n = 1..10000 FORMULA a(n) = A003415(A014574(n)). MATHEMATICA midQ[n_] := PrimeQ[n-1] && PrimeQ[n+1]; f[n_] := n * Total[#2 / #1 & @@@ FactorInteger[n]]; f /@ Select[Range[1500], midQ] (* Amiram Eldar, Nov 03 2019 *) CROSSREFS Cf. A003415, A014574, A078579. Sequence in context: A309759 A025617 A227855 * A092809 A250254 A293344 Adjacent sequences:  A078578 A078579 A078580 * A078582 A078583 A078584 KEYWORD nonn AUTHOR Reinhard Zumkeller, Nov 29 2002 STATUS approved

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Last modified May 27 01:29 EDT 2022. Contains 354092 sequences. (Running on oeis4.)