Invitation: celebrating 50 years of OEIS, 250000 sequences, and Sloane's 75th, there will be a conference at DIMACS, Rutgers, Oct 9-10 2014.
1,1
Table of n, a(n) for n=1..3.
a(n) = 2^(2*A000668(n)-1)/2-1 = A139296(n)-1.
Sequence in context: A198524 A208463 A172322 * A211251 A208469 A070907
Adjacent sequences: A139294 A139295 A139296 * A139298 A139299 A139300
bref,nonn
Omar E. Pol, Apr 13 2008
approved