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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.
2
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
1,1
PROG
(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
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
a(10) corrected, a(31)-a(46) added by Charles R Greathouse IV, Jun 05 2011
STATUS
approved