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Numbers of the form 7^j + 9^k, for j and k >= 0.
3

%I #7 Feb 18 2021 21:29:48

%S 2,8,10,16,50,58,82,88,130,344,352,424,730,736,778,1072,2402,2410,

%T 2482,3130,6562,6568,6610,6904,8962,16808,16816,16888,17536,23368,

%U 59050,59056,59098,59392,61450,75856,117650,117658,117730,118378,124210,176698,531442

%N Numbers of the form 7^j + 9^k, for j and k >= 0.

%H T. D. Noe, <a href="/A226831/b226831.txt">Table of n, a(n) for n = 1..10000</a>

%t 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]}]]]

%o (PARI) list(lim)=my(v=List(),J,K); for(j=0,logint((lim\=1)-1,7), J=7^j; K=1; while(J+K<=lim, listput(v,J+K); K*=9)); Set(v) \\ _Charles R Greathouse IV_, Feb 18 2021

%Y Cf. A004050 (2^j + 3^k), A226806-A226832 (cases to 8^j + 9^k).

%Y Cf. A226795 ((7^j + 9^k)/2).

%K nonn,easy

%O 1,1

%A _T. D. Noe_, Jun 19 2013