A394310 a(n) is the number of n-digit numbers that are not powers of primes.

1, 62, 742, 7913, 81580, 830966, 8413600, 84902275, 854911636, 8595788628, 86336979626, 866510090881, 8691542224682, 87141123346483, 873360370035565, 8750606225568966, 87655681172037954, 877883602836107139, 8790682286910283101, 88013238064412080119, 881093550115629692808

Offset

1,2

Links

Table of n, a(n) for n=1..21.

Formula

Limit_{n->oo} a(n)/a(n-1) = 10.

a(n) = A052268(n) - A304520(n) for n > 1.

Mathematica

a[n_]:=Module[{k=0}, For[i=10^(n-1), i<=10^n-1, i++, If[Length[FactorInteger[i]]>1, k++]]; k]; Array[a, 7]

Crossrefs

Cf. A024619, A052268, A304520.

Sequence in context: A196413 A131473 A138408 * A234482 A157499 A249235

Adjacent sequences: A394307 A394308 A394309 * A394311 A394312 A394313

Keyword

nonn,base

Author

Stefano Spezia, Mar 15 2026

Status

approved