Richard, since you also looked at this, would you think it is worth while submitting a %F or %C A107755 concerning the "gaps" (jumps of > factor 2): 2 > 8=2*(2+2) = a(2), 12 > 26=2*12+2 = a(4), 38 > 80=2*(38+2) = a(8), 120 > 242=2*120+2 = a(16), 362 > 728=2*(362+2) = a(32), 1092 > 2186 =2*362+2 = a(64), 3278 > 6560 =2*(3278+2) = a(128) ... Maximilian