A040164 |First digit - last digit| for n-th prime.

0, 0, 0, 0, 0, 2, 6, 8, 1, 7, 2, 4, 3, 1, 3, 2, 4, 5, 1, 6, 4, 2, 5, 1, 2, 0, 2, 6, 8, 2, 6, 0, 6, 8, 8, 0, 6, 2, 6, 2, 8, 0, 0, 2, 6, 8, 1, 1, 5, 7, 1, 7, 1, 1, 5, 1, 7, 1, 5, 1, 1, 1, 4, 2, 0, 4, 2, 4, 4, 6, 0, 6, 4, 0, 6, 0, 6, 4, 3, 5, 5, 3, 3, 1, 5, 1, 5, 3, 3, 1, 3, 5, 3, 3, 5, 2, 4, 4, 2, 4, 2, 2, 2, 4, 4

Offset: 1

Author

Felice Russo

Keywords

• nonn
• base
• easy

Crossrefs

Cf. A000040, A040163.

Programs

PARI

a(n) = my(pn = prime(n), digs = digits(pn)); abs(digs[1] - digs[#digs]); \\ Michel Marcus, Sep 27 2013

Formula

a(n) = A040163(A000040(n)). - Michel Marcus, Sep 27 2013

Extensions

Extended (and corrected) by Patrick De Geest, Jun 15 1999