A128761 Number of compositions of n with parts in N which avoid the pattern 123.

1, 1, 2, 4, 8, 16, 31, 61, 119, 232, 453, 883, 1721, 3354, 6536, 12735, 24813, 48344, 94189, 183506, 357518, 696534, 1357019, 2643798, 5150746, 10034865, 19550268, 38088486, 74205248, 144569092, 281654211, 548727863, 1069049370, 2082756500