not the diff. of two prime powers.

[N. J. A. Sloane]

I've added Don's version as A066510.  The two main sequences are now
(I only give the first 5 lines, see the database for the full, lengthy, entries)

%I A074981
%S A074321 6,14,34,42,50,58,62,66,70,78,82,86,90,102,110,114,130,134,158,178,
%T A074321 182,202,206,210,226,230,238,246,254,258,266,274,278,302,306,310,
%U A074321 314,322,326,330,358,374,378,390,394,398,402,410,418,422,426,430
%N A074981 Conjectured list of positive numbers which are not of the form m^p-n^q, where m,n,p,q are integers with m>0, n>0, p>1, q>1.
...

%I A066510
%S A066510 6,14,34,42,58,62,66,70,78,86,90,102,110,114,130,158,178,182,202,
%T A066510 210,230,238,254,258,266,274,278,302,306,310,314,322,326,330,358,
%U A066510 374,378,390,394,398,402,410,418,422,426,430,434,438,446,450,454
%N A066510 Conjectured list of positive numbers which are not of the form m^p-n^q, where m,n,p,q are integers with p>1, q>1.
...

and if you forget the sequence numbers, do what i do and refer
to the index, where there is this line:

powers, not the difference of two: A074981*, A074980, A069586, A023057, A066510

Neil


PS but wait a couple of hours before checking the database,
i'm in the middle of an update