OFFSET

1,4

COMMENTS

Original name: If p is the product of k1-th prime, k2-th prime,..,kr-th prime then set a(n)=n-k1*k2*..*kr, if p is the k-th prime then set=n-k, a(1)=1 by convention. - Michael De Vlieger, Oct 23 2023

LINKS

Michael De Vlieger, Table of n, a(n) for n = 1..10000

FORMULA

a(n) = n - A003963(n) for n>1.

MATHEMATICA

Array[# - Times @@ PrimePi@ Flatten[ConstantArray[#1, #2] & @@@ FactorInteger[#]] &, 74] (* Michael De Vlieger, Oct 23 2023 *)

CROSSREFS

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Jun 03 2010

EXTENSIONS

a(34) corrected by Georg Fischer, Dec 11 2022

Name edited by Michael De Vlieger, Oct 23 2023

STATUS

approved