A191369 Numbers n with k divisors such that n-1 and n+1 in binary representation have same number k of 0's as 1's.

11, 155, 203, 2164, 2228, 2252, 2276, 2348, 2404, 2452, 2468, 2588, 2612, 2636, 2644, 2675, 2708, 2763, 2836, 2891, 2979, 3148, 3179, 3236, 3275, 3283, 3411, 3475, 3716, 3971, 33723, 33755, 34235, 34523, 34539, 34715, 34771, 35315, 35563, 35571, 35787, 36155, 36411, 36507, 36555, 36579

Offset: 1

Author

Juri-Stepan Gerasimov, Jun 04 2011

Keywords

• nonn

Crossrefs

Cf. A030513, A030516, A030516, A191292.

Programs

PARI

isA191369(n)=my(b=vecsort(binary(n-1)),k=#b\2); #b==k+k & !b[k] & b[k+1] & b==vecsort(binary(n+1)) & numdiv(n)==k \\ Charles R Greathouse IV, Jun 05 2011

Extensions

a(10) corrected, a(31)-a(46) added by Charles R Greathouse IV, Jun 05 2011