%I #6 Apr 23 2018 02:57:44
%S 2,5,10,17,26,37,50,65,68,73,80,82,89,100,101,113,122,128,145,164,170,
%T 185,197,208,226,233,257,260,289,290,320,325,353,362,388,401,425,442,
%U 464,485,505,530,548,577,593,626,640,677,689,730,733,738,740,745,754,765,778
%N Numbers of the form a^2 + b^6, with integers a, b > 0.
%C A subsequence of A055394, the numbers of the form a^2 + b^3.
%C Although it is easy to produce many terms of this sequence, it is nontrivial to check whether a very large number is of this form.
%e The first terms are 1^2 + 1^6 = 2, 2^2 + 1^6 = 5, 3^2 + 1^6 = 10, 4^2 + 1^6 = 17, 5^2 + 1^6 = 26, ..., 8^2 + 1^6 = 1^2 + 2^6 = 65, 2^2 + 2^6 = 68, 3^2 + 2^6 = 73, ...
%o (PARI) is(n,k=2,m=6)=for(b=1,sqrtnint(n-1,m),ispower(n-b^m,k)&&return(b)) \\ Returns b > 0 if n is in the sequence, else 0.
%o A303372_vec(L=10^5,k=2,m=6,S=List())={for(a=1,sqrtnint(L-1,m),for(b=1,sqrtnint(L-a^m,k),listput(S,a^m+b^k)));Set(S)} \\ List of all terms up to limit L
%Y Cf. A055394 (a^2 + b^3), A111925 (a^2 + b^4), A100291 (a^4 + b^3), A100292 (a^5 + b^2), A100293 (a^5 + b^3), A100294 (a^5 + b^4).
%Y Cf. A303373 (a^3 + b^6), A303374 (a^4 + b^6), A303375 (a^5 + b^6).
%K nonn,easy
%O 1,1
%A _M. F. Hasler_, Apr 22 2018