A231626 Smallest sets of 5 consecutive deficient numbers in arithmetic progression. The initial deficient number is listed.

1, 7, 13, 31, 43, 49, 61, 73, 91, 115, 121, 127, 133, 145, 151, 163, 169, 181, 187, 211, 229, 235, 241, 247, 253, 265, 283, 289, 295, 313, 325, 331, 343, 347, 355, 373, 385, 403, 409, 421, 427, 433, 451, 469, 481, 505, 511, 523, 535, 553, 565, 583, 589, 595

Offset

1,2

Links

Shyam Sunder Gupta, Table of n, a(n) for n = 1..5000

Example

1, 2, 3, 4, 5 is the smallest set of 5 consecutive deficient numbers in arithmetic progression so 1 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 > 4, AppendTo[a, n - 4*cd]], m = 2; cd = n - z1]; z1 = n], {n, 3, 1000000}]; a

Crossrefs

Cf. A005100, A231623, A228962, A231624, A231625.

Sequence in context: A087196 A074963 A283937 * A343302 A110912 A240680

Adjacent sequences: A231623 A231624 A231625 * A231627 A231628 A231629

Keyword

nonn

Author

Shyam Sunder Gupta, Nov 11 2013

Status

approved