A231630 Smallest sets of 8 consecutive deficient numbers in arithmetic progression. The initial deficient number is listed.

221355125, 221355127, 402640539, 402640541, 668862579, 668862581, 739577139, 739577141

Offset

1,1

Links

Table of n, a(n) for n=1..8.

Example

221355125, 221355127, 221355129, 221355131, 221355133, 221355135, 221355137, 221355139 is the smallest set of 8 consecutive deficient numbers in arithmetic progression so 221355125 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 > 7, AppendTo[a, n - 7*cd]], m = 2; cd = n - z1]; z1 = n], {n, 3, 1000000000}]; a

Crossrefs

Cf. A005100, A231623, A228965, A231624, A231625, A231626, A231628, A231629.

Sequence in context: A114672 A268313 A268314 * A231092 A228965 A231093

Adjacent sequences: A231627 A231628 A231629 * A231631 A231632 A231633

Keyword

nonn

Author

Shyam Sunder Gupta, Nov 11 2013

Status

approved