A213394 The difference between n and the product of the digits of the n-th prime.

-1, -1, -2, -3, 4, 3, 0, -1, 3, -8, 8, -9, 9, 2, -13, 1, -28, 12, -23, 13, 0, -41, -1, -48, -38, 26, 27, 28, 29, 27, 17, 29, 12, 7, -1, 31, 2, 20, -3, 19, -22, 34, 34, 17, -18, -35, 45, 36, 21, 14, 33, -2, 45, 44, -15, 20, -51, 44, -39, 44, 13, 8, 63, 61, 56

Offset: 1

Author

Michael Turniansky, Jun 28 2012

Keywords

• base
• easy
• sign

Comments

The first three zeros occur at terms 7, 21 and 181440.

Links

• T. D. Noe, Table of n, a(n) for n = 1..10000

Programs

Mathematica

Table[n - Times @@ IntegerDigits[Prime[n]], {n, 100}] (* T. D. Noe, Jun 28 2012 *)

Formula

a(n) = A000027(n) - A053666(n).