A102885 Index of n in the primes A000040 or nonprimes A141468.

1, 2, 1, 2, 3, 3, 4, 4, 5, 6, 7, 5, 8, 6, 9, 10, 11, 7, 12, 8, 13, 14, 15, 9, 16, 17, 18, 19, 20, 10, 21, 11, 22, 23, 24, 25, 26, 12, 27, 28, 29, 13, 30, 14, 31, 32, 33, 15, 34, 35, 36, 37, 38, 16, 39, 40, 41, 42, 43, 17, 44, 18, 45, 46, 47, 48, 49, 19, 50, 51, 52, 20, 53, 21, 54

Offset

0,2

Comments

The nonnegative numbers n occur exactly once in either A000040 or A141468. The sequence lists the corresponding index. It is a permutation of A008619.

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Formula

A141468(a(n))=n or A000040(a(n))=n.

Mathematica

Module[{nn=80, pr, np}, pr=Prime[Range[PrimePi[nn]]]; np=Complement[ Range[ 0, nn], pr]; Table[If[PrimeQ[n], Position[pr, n], Position[np, n]], {n, 0, nn}]]//Flatten (* Harvey P. Dale, Sep 10 2022 *)

Crossrefs

Cf. A141468, A000040, A026233.

Sequence in context: A358024 A358025 A087188 * A323089 A239511 A264052

Adjacent sequences: A102882 A102883 A102884 * A102886 A102887 A102888

Keyword

nonn,easy

Author

Juri-Stepan Gerasimov, Aug 17 2008

Extensions

Edited by R. J. Mathar, Aug 19 2008

Status

approved