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 A078575 Sum of divisors of the average of n-th twin prime pair. 4
 7, 12, 28, 39, 72, 96, 168, 195, 216, 280, 288, 372, 546, 508, 468, 560, 744, 720, 576, 840, 840, 1344, 1240, 1152, 1170, 1440, 1860, 1248, 1296, 2016, 2178, 1656, 2184, 2016, 2223, 3024, 2640, 2976, 2340, 3136, 3315, 3024, 2808, 3168, 3072, 4320, 4032 (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) = A000203(A014574(n)). EXAMPLE 4th twin prime pair = (A001359(4), A006512(4)) = (17,19), hence A014574(4) = 18 with divisors = {1,2,3,6,9,18} therefore a(4) = 1+2+3+6+9+18 = 39. MATHEMATICA midQ[n_] := PrimeQ[n-1] && PrimeQ[n+1]; DivisorSigma[1, Select[Range[1500], midQ]] (* Amiram Eldar, Nov 03 2019 *) CROSSREFS Cf. A000203, A014574, A078574, A078576, A078577. Sequence in context: A104584 A223417 A224699 * A220036 A330589 A197229 Adjacent sequences:  A078572 A078573 A078574 * A078576 A078577 A078578 KEYWORD nonn AUTHOR Reinhard Zumkeller, Nov 29 2002 STATUS approved

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Last modified November 28 10:05 EST 2021. Contains 349401 sequences. (Running on oeis4.)