A113958 Triangular numbers that can be written as sum of two positive cubes.

28, 91, 351, 2926, 8001, 46971, 58653, 93528, 97461, 141778, 300700, 365085, 382375, 398278, 874503, 1295245, 1669878, 3425653, 4117015, 7517503, 7657741, 7771653, 9415630, 9598771

Offset

1,1

Comments

Intersection of A003325 and A000217.

Links

Donovan Johnson, Table of n, a(n) for n = 1..5122

Index entries for sequences related to sums of cubes

Example

91 = 13*(13+1)/2 = 4^3 + 3^3, therefore 91 is a term.

Mathematica

Sort[Select[Total/@Subsets[Range[300]^3, {2}], OddQ[Sqrt[8#+1]]&]] (* Harvey P. Dale, Oct 10 2014 *)

Prog

(PARI) T=thueinit('z^3+1);
has(n)=#select(v->min(v[1], v[2])>0, thue(T, n))>0
list(lim)=my(v=List()); for(n=7, (sqrtint(lim\1*8+1)-1)\2, my(t=n*(n+1)/2); if(has(t), listput(v, t))); Vec(v) \\ Charles R Greathouse IV, May 22 2026

Crossrefs

Cf. A000217, A000578, A003108, A003325, A119977.

Sequence in context: A065655 A341623 A272399 * A219815 A044215 A044596

Adjacent sequences: A113955 A113956 A113957 * A113959 A113960 A113961

Keyword

nonn

Author

Reinhard Zumkeller, Jun 03 2006

Status

approved