A328828 Index of the least significant digit larger than one in the primorial base expansion of n, 0 if no such digit exists.

0, 0, 0, 0, 2, 2, 0, 0, 0, 0, 2, 2, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 2, 2, 0, 0, 0, 0, 2, 2, 0, 0, 0, 0, 2, 2, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 2, 2, 4, 4, 4, 4, 2, 2, 4, 4, 4, 4, 2, 2, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 2, 2, 3, 3, 3, 3, 2, 2, 4, 4, 4, 4, 2, 2, 4, 4, 4, 4, 2, 2, 3, 3, 3, 3

Offset

0,5

Links

Antti Karttunen, Table of n, a(n) for n = 0..65537

Index entries for sequences related to primorial base.

Formula

a(n) = A277885(A276086(n)) = A055396(A328572(n)).

Mathematica

a[n_] := Module[{k = n, p = 2, s = {}, r, i}, While[{k, r} = QuotientRemainder[k, p]; k != 0 || r != 0, AppendTo[s, r]; p = NextPrime[p]]; i = FirstPosition[s, _?(# > 1 &)]; If[MissingQ[i], 0, i[[1]]]]; Array[a, 100] (* Amiram Eldar, Mar 13 2024 *)

Prog

(PARI) A328828(n) = { my(i=1, p=2); while(n, if((n%p)>1, return(i)); i++; n = n\p; p = nextprime(1+p)); (0); };

Crossrefs

Cf. A049345, A055396, A276086, A277885, A328572.

Sequence in context: A354107 A037863 A163536 * A276009 A328842 A113302

Adjacent sequences: A328825 A328826 A328827 * A328829 A328830 A328831

Keyword

nonn,base

Author

Antti Karttunen, Oct 29 2019

Status

approved