OFFSET
1,1
COMMENTS
A073490(a(n)) = 2.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
EXAMPLE
220 is a term, as 220 = 2*2*5*11 with two gaps: between 2 and 5 and between 5 and 11.
MATHEMATICA
pa[n_, k_] := If[k == NextPrime[n], 0, 1]; Select[Range[645], Total[pa @@@ Partition[First /@ FactorInteger[#], 2, 1]] == 2 &] (* Jayanta Basu, Jul 01 2013 *)
PROG
(Haskell)
a073494 n = a073494_list !! (n-1)
a073494_list = filter ((== 2) . a073490) [1..]
-- Reinhard Zumkeller, Dec 20 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Aug 03 2002
STATUS
approved