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

Author

Zak Seidov, May 25 2010

Keywords

• nonn

Examples

			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).
		

Links

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

Crossrefs

Intersection of A005237 and A030630.

Programs

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 *)

PARI

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