A073261 Length of FixedPointList approximating (2^n)-th composite number. See program link below.

4, 4, 3, 3, 3, 4, 3, 5, 4, 4, 5, 4, 5, 6, 6, 6, 6, 5, 6, 6, 7, 6, 6, 6, 7, 7, 8, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 10, 10, 9, 10

Offset: 0

Author

Labos Elemer, Jul 22 2002

Keywords

• nonn

Comments

Number of iterations needed to reach the composite number using the formula in the program.

Examples

			n=30: {1073741824, 1128141853, 1130754984, 1130880243, 1130886219, 1130886489, 1130886503, 1130886504}, so a(30)=8.
		

Crossrefs

Cf. A002808, A073255-A073264, A065856.

Programs

Mathematica

Table[ Length[ FixedPointList[ 2^n+PrimePi[ # ]+1 &, 2^n]]-1, {n, 0, 45}]

Extensions

Extended by Robert G. Wilson v, Jul 24 2002