A100546 Difference between the smallest semiperimeter (see A063655) and its integer log (A001414) equals 1.

2, 3, 5, 7, 11, 13, 17, 18, 19, 23, 24, 29, 30, 31, 37, 41, 42, 43, 47, 53, 59, 61, 66, 67, 71, 73, 78, 79, 83, 89, 97, 101, 102, 103, 107, 109, 113, 114, 127, 131, 137, 138, 139, 149, 151, 157, 163, 167, 173, 174, 179, 181, 186, 191, 193, 197, 199, 211, 222, 223, 227

Offset: 0

Author

Carlos Alves, Dec 31 2004

Keywords

• nonn

Comments

Theorem: Except for 24, the sequence is the union of primes and 6*primes.

Examples

			Any prime p, since it has semiperimeter p+1 and its integer log is p.
		

Crossrefs

Cf. A001414 and A063655.

Programs

Mathematica

logint = Function[n, Module[{vn}, vn = Transpose[FactorInteger[n]];vn[[1]].vn[[2]] ]]; semiperi = Function[n, Min[Divisors[n] + Reverse[Divisors[n]]]]; sq = {}; Do[If[semiperi[k] == logint[k] + 1, AppendTo[sq, k]], {k, 2, 500}]; sq