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 A231628 Smallest sets of 6 consecutive deficient numbers in arithmetic progression. The initial deficient number is listed. 3
 2987, 4727, 9723, 18843, 22983, 30543, 35147, 39947, 45047, 50463, 55787, 56807, 58055, 58779, 69183, 78047, 81947, 85743, 101147, 106143, 108255, 109247, 117123, 134087, 139743, 139803, 152567, 171287, 174347, 175907, 182643, 189767, 197027, 199803, 202127 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Shyam Sunder Gupta, Table of n, a(n) for n = 1..5000 EXAMPLE 2987, 2989, 2991, 2993, 2995, 2997 is the smallest set of 6 consecutive deficient numbers in arithmetic progression so 2987 is in the list. MATHEMATICA DefQ[n_] := DivisorSigma[1, n] < 2 n; m = 2; z1 = 2; cd = 1; a = {}; Do[If[DefQ[n], If[n - z1 == cd, m = m + 1; If[m > 5, AppendTo[a, n - 5*cd]], m = 2; cd = n - z1]; z1 = n], {n, 3, 1000000}]; a CROSSREFS Cf. A005100, A231623, A228963, A231624, A231625, A231626. Sequence in context: A120373 A186866 A252571 * A231623 A108926 A159731 Adjacent sequences:  A231625 A231626 A231627 * A231629 A231630 A231631 KEYWORD nonn AUTHOR Shyam Sunder Gupta, Nov 11 2013 STATUS approved

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Last modified January 25 01:10 EST 2021. Contains 340414 sequences. (Running on oeis4.)