A087611 a(n) = (prime(n) - 1) mod n.

0, 0, 1, 2, 0, 0, 2, 2, 4, 8, 8, 0, 1, 0, 1, 4, 7, 6, 9, 10, 9, 12, 13, 16, 21, 22, 21, 22, 21, 22, 2, 2, 4, 2, 8, 6, 8, 10, 10, 12, 14, 12, 18, 16, 16, 14, 22, 30, 30, 28, 28, 30, 28, 34, 36, 38, 40, 38, 40, 40, 38, 44, 54, 54, 52, 52, 62, 64, 1, 68, 68, 70, 1, 2, 3, 2, 3, 6, 5, 8

Offset: 1

Author

Reinhard Zumkeller, Sep 11 2003

Keywords

• nonn
• easy

Crossrefs

Cf. A023143 (indices of 0's).

Cf. A006093, A004648.

Programs

Magma

[((NthPrime(n) -1) mod n): n in [1..100]]; // Vincenzo Librandi, Apr 06 2011

PARI

a(n) = (prime(n)-1) % n; \\ Kevin Ryde, Feb 03 2023