A355037 a(n) is the product of the digits of n in primorial base.

0, 1, 0, 1, 0, 2, 0, 0, 0, 1, 0, 2, 0, 0, 0, 2, 0, 4, 0, 0, 0, 3, 0, 6, 0, 0, 0, 4, 0, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 2, 0, 0, 0, 2, 0, 4, 0, 0, 0, 3, 0, 6, 0, 0, 0, 4, 0, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 4, 0, 0, 0, 4, 0, 8, 0, 0, 0, 6, 0, 12, 0, 0, 0

Offset: 0

Author

Rémy Sigrist, Jun 16 2022

Keywords

• nonn
• look
• base

Examples

			The first terms, alongside the digits of n in primorial base, are:
  n   a(n)  pr(n)
  --  ----  -----
   0     0      0
   1     1      1
   2     0    1_0
   3     1    1_1
   4     0    2_0
   5     2    2_1
   6     0  1_0_0
   7     0  1_0_1
   8     0  1_1_0
   9     1  1_1_1
  10     0  1_2_0
  11     2  1_2_1
  12     0  2_0_0
  13     0  2_0_1
  14     0  2_1_0
  15     2  2_1_1
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 0..10000
• Index entries for sequences related to primorial base

Crossrefs

Cf. A143293, A208575, A235168, A328574, A328581.

Programs

PARI

a(n) = { my (p=1); forprime (r=2, oo, p*=n%r; n\=r; if (p==0 || n==0, return (p))) }

Formula

a(n) = 1 iff n belongs to A143293.

a(n) > 0 iff n belongs to A328574 \ {0}.