A077656 Numbers having a different number of prime factors as their successors (counted with multiplicity).

1, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 15, 16, 17, 18, 19, 20, 22, 23, 24, 26, 28, 29, 30, 31, 32, 35, 36, 37, 39, 40, 41, 42, 43, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 76, 77, 78, 79, 80, 81, 82, 83

Offset: 1

Author

Reinhard Zumkeller, Nov 13 2002

Keywords

• nonn

Comments

A077655(a(n))=0; A001222(a(n))<>A001222(a(n)+1).

Examples

			20=2*2*5 and 20+1=21=3*7: A001222(20)<>A001222(21), therefore 20 is a term (A077655(20)=0).
		

Crossrefs

Cf. A001222, A045920.

Programs

Mathematica

Position[Partition[PrimeOmega[Range[100]],2,1],?(#[[1]]!=#[[2]]&),{1}, Heads->False]//Flatten (* _Harvey P. Dale, Sep 19 2016 *)