A180106 Semiprimes which are the sum of three distinct positive cubes of semiprime numbers in two or more distinct ways.

88073, 195905, 196057, 196841, 205102, 211466, 610903, 747209, 809966, 1078622, 1543267, 1828441, 1967402, 2143783, 2312029, 2803501, 3055258, 3108673, 3244466, 3477629, 3662567, 4237577, 4770137, 5741074, 5835593, 5908889, 7189265, 7497118, 8438249, 8742781

Offset

1,1

Comments

610903 = 74^3+55^3+34^3 = 82^3+39^3+6^3.

88073 = 29*3037 = 21^3+33^3+35^3 = 25^3+26^3+38^3. - Chai Wah Wu, May 20 2017

Links

Chai Wah Wu, Table of n, a(n) for n = 1..10000

Mathematica

f[n_] := PrimeOmega@ n == 2; lst = {}; Do[Do[Do[If[And[f[a], f[b], f[c], f[p = a^3 + b^3 + c^3]], AppendTo[lst, p]], {c, b - 1, 1, -1}], {b, a - 1, 1, -1}], {a, 200}]; lst1 = Sort@ lst; lst = {}; Do[If[lst1[[n]] == lst1[[n + 1]], AppendTo[lst, lst1[[n]]]], {n, Length[lst1] - 1}]; lst (* Corrected by Michael De Vlieger, May 21 2017 *)

Crossrefs

Cf. A011541, A024974, A025400, A122723, A180088, A180089, A180099

Sequence in context: A183658 A234442 A204508 * A190382 A068536 A183728

Adjacent sequences: A180103 A180104 A180105 * A180107 A180108 A180109

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Aug 10 2010

Extensions

Terms corrected by Chai Wah Wu, May 20 2017

Status

approved