OFFSET
1,2
MATHEMATICA
a = 7; b = 9; mx = 600000; Union[Flatten[Table[a^n + b^m, {m, 0, Log[b, mx]}, {n, 0, Log[a, mx - b^m]}]]]/2
PROG
(PARI) list(lim)=my(v=List(), J, K); lim=(lim\1)*2; for(j=0, logint(lim-1, 7), J=7^j; K=1; while(J+K<=lim, listput(v, (J+K)/2); K*=9)); Set(v) \\ Charles R Greathouse IV, Feb 18 2021
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
T. D. Noe, Jun 19 2013
STATUS
approved