A145340 a(n) = the maximum of d(p(n)-1) and d(p(n)+1), where d(m) is the number of divisors of m and p(n) is the n-th prime.

2, 3, 4, 4, 6, 6, 6, 6, 8, 8, 8, 9, 8, 8, 10, 8, 12, 12, 8, 12, 12, 10, 12, 12, 12, 9, 8, 12, 12, 10, 12, 12, 8, 12, 12, 12, 12, 10, 16, 8, 18, 18, 14, 14, 12, 12, 16, 12, 12, 12, 12, 20, 20, 18, 9, 16, 16, 16, 12, 16, 8, 12, 12, 16, 16, 8, 16, 20, 12, 12, 12, 24, 10, 12, 16, 16, 16

Offset: 1

Author

Leroy Quet, Oct 08 2008

Keywords

• nonn

Crossrefs

Cf. A145339, A008328, A008329, A067889, A103664, A103665.

Programs

Mathematica

Table[Max[DivisorSigma[0, Prime[n]-1], DivisorSigma[0, Prime[n]+1]], {n, 1, 100}] (* Stefan Steinerberger, Oct 11 2008 *)

Extensions

More terms from Stefan Steinerberger and Ray Chandler, Oct 11 2008