A062969 Numbers k such that abs(d(k)-k-1) is prime, where d(k) is the number of divisors of k.

3, 4, 6, 8, 9, 10, 12, 14, 18, 22, 24, 25, 26, 28, 30, 34, 46, 49, 52, 54, 62, 66, 72, 74, 76, 78, 80, 82, 84, 86, 90, 104, 106, 108, 110, 112, 114, 134, 138, 142, 150, 160, 166, 169, 170, 172, 174, 176, 180, 186, 192, 194, 202, 204, 208, 214, 226, 230, 234, 244, 246

Offset

1,1

Links

Table of n, a(n) for n=1..61.

Example

d(300)-300-1 = -283, absolute value of which is prime.

Prog

(PARI) j=[]; for(n=1, 300, if(isprime(numdiv(n)-n-1), j=concat(j, n))); j

Crossrefs

Cf. A062968.

Sequence in context: A182829 A112800 A294456 * A175035 A025063 A050849

Adjacent sequences: A062966 A062967 A062968 * A062970 A062971 A062972

Keyword

easy,nonn

Author

Jason Earls, Jul 23 2001

Status

approved