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A228964 Smallest sets of 7 consecutive abundant numbers in arithmetic progression. The initial abundant number is listed. 3
1242, 6702, 7962, 12162, 13842, 15522, 16362, 18042, 18882, 19722, 24762, 26442, 27282, 27702, 28122, 28962, 36942, 38202, 39462, 43662, 44922, 45762, 48282, 48702, 51222, 55842, 56682, 60042, 62562, 63402, 66762, 69282, 69702, 70962, 71802, 73062, 73482 (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

1242, 1248, 1254, 1260, 1266, 1272, 1278 is the smallest set of 7 consecutive abundant numbers in arithmetic progression so 1242 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 > 6, AppendTo[a, n - 6*cd]], m = 2; cd = n - z1]; z1 = n], {n, 19, 1000000}]; a

Select[Partition[Select[Range[80000], DivisorSigma[1, #]>2#&], 7, 1], Length[ Union[ Differences[#]]] ==1&][[All, 1]] (* Harvey P. Dale, Oct 15 2017 *)

CROSSREFS

Cf. A005101, A228433, A228844, A228961, A228962, A228963.

Sequence in context: A028514 A099178 A209711 * A047628 A181073 A023065

Adjacent sequences:  A228961 A228962 A228963 * A228965 A228966 A228967

KEYWORD

nonn

AUTHOR

Shyam Sunder Gupta, Nov 10 2013

STATUS

approved

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Last modified June 16 19:43 EDT 2019. Contains 324155 sequences. (Running on oeis4.)