OFFSET
0,2
COMMENTS
Number of inequivalent binary linear codes of length <= n. Also the total number of nonisomorphic binary matroids on an k-set for all k <= n. The subsequence of primes is: 3, 7, 31, 131.
EXAMPLE
a(14) = 1 + 2 + 4 + 8 + 16 + 32 + 68 + 148 + 342 + 848 + 2297 + 6928 + 24034 + 98854 + 503137 = 636719 is prime.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jonathan Vos Post, Nov 30 2010
STATUS
approved