A328585 Numbers n for which A257993(n) is equal to A257993(A276086(A276086(n))), where A276086 converts the primorial base expansion of n into its prime product form, and A257993 returns the index of the least prime not present in its argument.

1, 3, 5, 6, 7, 9, 11, 13, 15, 17, 18, 19, 21, 23, 25, 27, 29, 31, 33, 35, 36, 37, 39, 41, 43, 45, 47, 48, 49, 51, 53, 55, 57, 59, 61, 63, 65, 66, 67, 69, 71, 73, 75, 77, 78, 79, 81, 83, 85, 87, 89, 91, 93, 95, 96, 97, 99, 101, 103, 105, 107, 108, 109, 111, 113, 115, 117, 119, 121, 123, 125, 126, 127, 129, 131, 133, 135, 137, 138, 139

Offset: 1

Author

Antti Karttunen, Oct 21 2019

Keywords

• nonn

Comments

Numbers n for which A257993(n) is equal to A328578(n).

All odd numbers are included, as A257993(2n+1) = A328578(2n+1) = 1 for all n >= 0.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000
• Index entries for sequences related to primorial base

Crossrefs

Union of A005408 (odd numbers) and A328586 (even terms).

Positions of zeros in A328590.

Cf. A257993, A276086, A328578, A328587, A328588.

Cf. also A328316, A328317.

Programs

PARI

A257993(n) = { for(i=1,oo,if(n%prime(i),return(i))); }
A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
A328578(n) = A257993(A276086(A276086(n)));
isA328585(n) = (A328578(n) == A257993(n));