A137366 Subsequence of A137365 where it is possible to choose p1, p2, p3 so that p1+p2+p3 = prime.
1483, 5381, 6271, 7229, 9181, 11897, 13103, 13841, 14489, 17107, 20357, 25747, 26711, 27917, 30161, 30259, 31247, 32579, 36677, 36899, 36901, 42083, 48817, 54181, 55511, 55691, 56377, 57637, 64151, 66347, 69389, 75167, 76031, 76123
Offset: 1
Keywords
Examples
1483=3^3+5^3+11^3, 3+5+11=17; 7229=3^3+7^3+19^3, 3+7+19=29.
Links
- R. J. Mathar and Vincenzo Librandi, Table of n, a(n) for n = 1..350 (first 44 terms from R. J. Mathar)
Programs
-
Mathematica
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]] 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 *)
Comments