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.

A137366 Subsequence of A137365 where it is possible to choose p1, p2, p3 so that p1+p2+p3 = prime.

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%I A137366 #14 Mar 05 2024 14:46:42
%S A137366 1483,5381,6271,7229,9181,11897,13103,13841,14489,17107,20357,25747,
%T A137366 26711,27917,30161,30259,31247,32579,36677,36899,36901,42083,48817,
%U A137366 54181,55511,55691,56377,57637,64151,66347,69389,75167,76031,76123
%N A137366 Subsequence of A137365 where it is possible to choose p1, p2, p3 so that p1+p2+p3 = prime.
%C A137366 36161 is the first number that is in A137365 but not in the present sequence. See A138556.
%H A137366 R. J. Mathar and Vincenzo Librandi, <a href="/A137366/b137366.txt">Table of n, a(n) for n = 1..350</a> (first 44 terms from R. J. Mathar)
%e A137366 1483=3^3+5^3+11^3, 3+5+11=17;
%e A137366 7229=3^3+7^3+19^3, 3+7+19=29.
%t A137366 Array[r, 99]; Array[y, 99]; For[i = 0, i < 10^2, r[i] = y[i] = 0; i++ ]; z = 4^2; n = 0; For[i1 = 1, i1 < z, a = Prime[i1]; a2 = a^3; For[i2 = i1 + 1, i2 < z, b = Prime[i2]; b2 = b^3; For[i3 = i2 + 1, i3 < z, c = Prime[i3]; c2 = c^3; p = a2 + b2 + c2; p3 = a + b + c; If[PrimeQ[p] && PrimeQ[p3], Print[a2, " + ", b2, " + ", c2, " = ", p, "; ", a, " + ", b, " + ", c, " = ", p3]; n++; r[n] = p]; i3++ ]; i2++ ]; i1++ ]; Sort[Array[r, 71]]
%t A137366 lst = {}; Do[q = Prime@a; r = Prime@b; s = Prime@c; p = q^3 + r^3 + s^3; t = q + r + s; If[PrimeQ@p && PrimeQ@t, AppendTo[lst, p]], {a, 14}, {b, a - 1}, {c, b - 1}]; Take[Sort@lst, 35] (* _Robert G. Wilson v_, Apr 13 2008 *)
%Y A137366 Cf. A137365, A138556.
%K A137366 nonn
%O A137366 1,1
%A A137366 _Vladimir Joseph Stephan Orlovsky_, Apr 09 2008, Apr 14 2008