Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
A040164
|First digit - last digit| for n-th prime.
6
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
1,6
FORMULA
a(n) = A040163(A000040(n)). - Michel Marcus, Sep 27 2013
PROG
(PARI) a(n) = my(pn = prime(n), digs = digits(pn)); abs(digs[1] - digs[#digs]); \\ Michel Marcus, Sep 27 2013
CROSSREFS
Sequence in context: A021377 A261875 A084686 * A086353 A019786 A278497
KEYWORD
nonn,base,easy
AUTHOR
EXTENSIONS
Extended (and corrected) by Patrick De Geest, Jun 15 1999
STATUS
approved