A174456 Numbers k such that d(k) = d(k+1) = 12.

735, 819, 1035, 1196, 1274, 1275, 1449, 1665, 1924, 1925, 1952, 1988, 2324, 2331, 2540, 2655, 3068, 3195, 3267, 3324, 3339, 3549, 3555, 3626, 3717, 4164, 4220, 4235, 4556, 4563, 4598, 4635, 4675, 4796, 5024, 5084, 5324, 5525, 5588, 5634, 5660, 6003

Offset

1,1

Links

Zak Seidov, Table of n, a(n) for n = 1..71998

Example

a(1) =  735 = A030630(67)  = A030630(68)  - 1 = A005237(88);
a(2) =  819 = A030630(76)  = A030630(77)  - 1 = A005237(99);
a(3) = 1035 = A030630(100) = A030630(101) - 1 = A005237(124).

Mathematica

Select[Range[10^7], DivisorSigma[0, {#, #+1}]=={12, 12}&]
Transpose[SequencePosition[DivisorSigma[0, Range[6500]], {12, 12}]][[1]] (* The program uses the SequencePosition function from Mathematica version 10 *) (* Harvey P. Dale, Jul 16 2016 *)

Prog

(PARI) is(n)=numdiv(n)==12 && numdiv(n+1)==12 \\ Charles R Greathouse IV, Jun 19 2016

Crossrefs

Intersection of A005237 and A030630.

Sequence in context: A025348 A126556 A349870 * A306474 A250053 A227755

Adjacent sequences: A174453 A174454 A174455 * A174457 A174458 A174459

Keyword

nonn

Author

Zak Seidov, May 25 2010

Status

approved