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 A228961 Smallest sets of 4 consecutive abundant numbers in arithmetic progression. The initial abundant number is listed. 6
 114, 120, 228, 234, 240, 282, 348, 420, 582, 588, 654, 660, 708, 840, 1002, 1008, 1014, 1068, 1122, 1242, 1248, 1254, 1260, 1380, 1434, 1542, 1548, 1674, 1794, 1800, 1908, 1914, 1998, 2094, 2100, 2208, 2214, 2220, 2262, 2268, 2328, 2334, 2340, 2502, 2508 (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 114, 120, 126, 132 is the smallest set of 4 consecutive abundant numbers in arithmetic progression so 114 is in the list. MATHEMATICA AbundantQ[n_] := DivisorSigma[1, n] > 2 n; m = 2; z1 = 18; cd = 6; a = {}; Do[If[AbundantQ[n], If[n - z1 == cd, m = m + 1; If[m > 3, AppendTo[a, n - 3*cd]], m = 2; cd = n - z1]; z1 = n], {n, 19, 1000000}]; a CROSSREFS Cf. A005101, A228433, A228844. Sequence in context: A138693 A272303 A260213 * A057440 A113537 A352233 Adjacent sequences: A228958 A228959 A228960 * A228962 A228963 A228964 KEYWORD nonn AUTHOR Shyam Sunder Gupta, Nov 10 2013 STATUS approved

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Last modified March 4 16:59 EST 2024. Contains 370532 sequences. (Running on oeis4.)