login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A073492
Numbers having at least one prime gap in their factorization.
45
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
1,1
COMMENTS
A073490(a(n)) > 0.
A137794(a(n))=0, complement of A073491. - Reinhard Zumkeller, Feb 11 2008
LINKS
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 *)
PROG
(Haskell)
a073492 n = a073492_list !! (n-1)
a073492_list = filter ((> 0) . a073490) [1..]
-- Reinhard Zumkeller, Dec 20 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Aug 03 2002
STATUS
approved