cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A066649 Primes of the form a^2 + b^3 with a, b > 0.

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%I A066649 #14 Mar 12 2025 08:15:34
%S A066649 2,5,17,31,37,43,73,89,101,113,127,197,223,233,241,257,269,283,337,
%T A066649 347,353,359,379,401,443,449,487,521,577,593,599,677,701,733,743,811,
%U A066649 827,829,919,953,1009,1019,1049,1051,1097,1129,1153,1213,1289,1297,1361
%N A066649 Primes of the form a^2 + b^3 with a, b > 0.
%H A066649 T. D. Noe, <a href="/A066649/b066649.txt">Table of n, a(n) for n = 1..10000</a>
%H A066649 Jori Merikoski, <a href="https://arxiv.org/abs/2503.05396">On primes represented by aX^2+bY^3aX^2+bY^3</a>, arXiv preprint (2025). arXiv:2503.05396 [math.NT]
%F A066649 On Conjecture C_a(1/17), this sequence is infinite and a(n) << n^(6/5) log n, see Merikoski link. - _Charles R Greathouse IV_, Mar 11 2025
%e A066649 A000040(26) = 101 = 10^2 + 1^3, therefore 101 is a term.
%e A066649 A000040(51) = a(13) = 233 = 225 + 8 = 15^2 + 2^3.
%t A066649 lst={};Do[Do[p=n^2+m^3;If[PrimeQ[p],AppendTo[lst,p]],{n,5!}],{m,5!}];Take[Union[lst],123] (* _Vladimir Joseph Stephan Orlovsky_, May 24 2009 *)
%o A066649 (PARI) list(lim)=my(v=List()); for(y=1,sqrtnint(lim\=1,3), my(y3=y^3); for(x=1,sqrtint(lim-y3), my(p=y3+x^2); if(isprime(p), listput(v,p)))); Set(v) \\ _Charles R Greathouse IV_, Mar 11 2025
%Y A066649 Cf. A055394, A066650.
%Y A066649 Cf. A000040, A078393, A078390.
%K A066649 nonn
%O A066649 1,1
%A A066649 _Reinhard Zumkeller_, Dec 17 2001