A079890 Least number > n having one more prime factor than n, not necessarily distinct.

2, 4, 4, 8, 6, 8, 9, 16, 12, 12, 14, 16, 14, 18, 18, 32, 21, 24, 21, 24, 27, 27, 25, 32, 27, 27, 36, 36, 33, 36, 33, 64, 42, 42, 42, 48, 38, 42, 42, 48, 46, 54, 46, 54, 54, 50, 49, 64, 50, 54, 52, 54, 55, 72, 63, 72, 63, 63, 62, 72, 62, 63, 81, 128, 66, 81, 69, 81, 70, 81, 74, 96

Offset

1,1

Comments

A001222(a(n)) = A001222(n) + 1;

a(2^k) = 2^(k+1).

a(A076156(n)) = A076156(n)+1. - Reinhard Zumkeller, Feb 01 2008

Links

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

Mathematica

lng[n_]:=Module[{x=n+1, pon=PrimeOmega[n]}, While[PrimeOmega[x]-pon!=1, x++]; x]; Array[lng, 80] (* Harvey P. Dale, Nov 09 2011 *)

Prog

(Haskell)
a079890 n = head [x | x <- [n + 1 ..], a001222 x == 1 + a001222 n]
-- Reinhard Zumkeller, Aug 29 2013

Crossrefs

Cf. A079891, A079892.

Cf. A165712.

Sequence in context: A229913 A285326 A355467 * A337973 A223592 A180444

Adjacent sequences: A079887 A079888 A079889 * A079891 A079892 A079893

Keyword

nonn,nice

Author

Reinhard Zumkeller, Jan 14 2003

Status

approved