OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..30
J. Overbey, W. Traves and J. Wojdylo, On the Keyspace of the Hill Cipher.
FORMULA
a(n) = (7^n - 1)*(7^n - 7)*...*(7^n - 7^(n-1)).
MATHEMATICA
Table[Product[7^n - 7^k, {k, 0, n-1}], {n, 0, 10}] (* Vincenzo Librandi, Jan 28 2013 *)
PROG
(Magma) [1] cat [&*[(7^n - 7^k): k in [0..n-1]]: n in [1..7]]; // Bruno Berselli, Jan 28 2013
(PARI) for(n=0, 10, print1(prod(k=0, n-1, 7^n - 7^k), ", ")) \\ G. C. Greubel, May 31 2018
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Stephen G Penrice, Mar 04 2000
EXTENSIONS
More terms from Vladeta Jovovic, Mar 16 2000
STATUS
approved