A180088 -id:A180088 - cp's OEIS frontend

A180089 Semiprimes which are the sum of three distinct positive cubes in two or more distinct ways.

1366, 1457, 1793, 1945, 3599, 4105, 5435, 7379, 8315, 9017, 10261, 10963, 11773, 12706, 13957, 15163, 15371, 15553, 15751, 15758, 16271, 17263, 17354, 17947, 18649, 19027, 19369, 19657, 19729, 19774, 19781, 19907, 21026, 21167, 22411

Offset: 1

Vladimir Joseph Stephan Orlovsky, Aug 09 2010

nonn

2^3+3^3+11^3=5^3+8^3+9^3=1366=2*683, 1^3+5^3+11^3=6^3+8^3+9^3=1457=31*47,..

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

Cf. A011541, A024974, A025400, A122723, A180088

f[n_]:=Last/@FactorInteger[n]=={1,1}; lst={};Do[Do[Do[If[f[p=a^3+b^3+c^3],AppendTo[lst,p]],{c,b-1,1,-1}],{b,a-1,1,-1}],{a,55}];lst1=Sort@lst; lst={};Do[If[lst1[[n]]==lst1[[n+1]],AppendTo[lst,lst1[[n]]]],{n,Length[lst1]-1}];lst

A180099 Primes which are the sum of three distinct positive cubes of prime numbers in two or more distinct ways.

Original entry on oeis.org

185527, 451837, 591751, 1265471, 1266929, 1618973, 1626227, 1664713, 2586277, 2754683, 2765519, 2805193, 3422303, 3740309, 3748499, 4154779, 5336479, 5483953, 5557987, 6130151, 6586091, 7231013, 7361801, 7726571, 8205553

Offset: 1

Vladimir Joseph Stephan Orlovsky, Aug 09 2010

nonn

			185527 = 47^3+43^3+13^3=53^3+31^3+19^3.

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

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

lst={};Do[Do[Do[If[PrimeQ[p=Prime[a]^3+Prime[b]^3+Prime[c]^3],AppendTo[lst,p]],{c,b-1,1,-1}],{b,a-1,1,-1}],{a,88}];lst1=Sort@lst; lst={};Do[If[lst1[[n]]==lst1[[n+1]],AppendTo[lst,lst1[[n]]]],{n,Length[lst1]-1}];lst
Select[Tally[Select[Total/@Subsets[Prime[Range[50]]^3,{3}],PrimeQ]],#[[2]]> 1&] [[All,1]]//Sort (* Harvey P. Dale, Sep 26 2020 *)

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

Original entry on oeis.org

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

Vladimir Joseph Stephan Orlovsky, Aug 10 2010

nonn

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

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

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

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 *)

Terms corrected by Chai Wah Wu, May 20 2017

cp's OEIS Frontend

A180089 Semiprimes which are the sum of three distinct positive cubes in two or more distinct ways.

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A180099 Primes which are the sum of three distinct positive cubes of prime numbers in two or more distinct ways.

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

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