A073492 Numbers having at least one prime gap in their factorization.

10, 14, 20, 21, 22, 26, 28, 33, 34, 38, 39, 40, 42, 44, 46, 50, 51, 52, 55, 56, 57, 58, 62, 63, 65, 66, 68, 69, 70, 74, 76, 78, 80, 82, 84, 85, 86, 87, 88, 91, 92, 93, 94, 95, 98, 99, 100, 102, 104, 106, 110, 111, 112, 114, 115, 116, 117, 118, 119, 122, 123, 124, 126

Offset: 1

Author

Reinhard Zumkeller, Aug 03 2002

Keywords

• nonn

Comments

A073490(a(n)) > 0.

A137794(a(n))=0, complement of A073491. - Reinhard Zumkeller, Feb 11 2008

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A005117, A073493, A073494, A073495, A073491, A073486.

Programs

Haskell

a073492 n = a073492_list !! (n-1)
a073492_list = filter ((> 0) . a073490) [1..]
-- Reinhard Zumkeller, Dec 20 2013

Mathematica

pa[n_, k_] := If[k == NextPrime[n], 0, 1]; Select[Range[126],Total[pa @@@ Partition[First /@ FactorInteger[#], 2, 1]] > 0 &] (* Jayanta Basu, Jul 01 2013 *)