A038596 Squares that are a difference between 2 positive cubes.

169, 784, 2401, 10816, 21609, 32761, 35721, 50176, 123201, 130321, 150544, 153664, 257049, 301401, 345744, 456976, 571536, 692224, 1058841, 1382976, 1750329, 1874161, 2030625, 2096704, 2286144, 2640625, 3211264, 3467044, 3651921, 3694084, 5285401, 5546025

Offset

1,1

Links

Donovan Johnson, Table of n, a(n) for n = 1..1000

Formula

a(n) = A038597(n)^2. - M. F. Hasler, Oct 05 2013

Prog

(PARI) is(n)=for(k=sqrtnint(n, 3)+1, (sqrtint(12*n-3)+3)\6, if(ispower(n-k^3, 3), return(issquare(n)))); 0 \\ Charles R Greathouse IV, Oct 28 2013
(PARI) mm=820188; cb=vector(mm); for(i=1, mm, cb[i]=i^3); mb=1420608; v=vector(mb); mx=mb^2; for(i=1, mm-1, for(j=i+1, mm, d=cb[j]-cb[i]; if(d<=mx, if(issquare(d, &r), v[r]=1), next(2)))); c=0; for(n=1, mb, if(v[n]==1, c++; write("b038596.txt", c " " n^2))) \\ Donovan Johnson, Oct 31 2013

Crossrefs

Cf. A038593-A038598.

Sequence in context: A294307 A017534 A120904 * A250988 A289338 A256979

Adjacent sequences: A038593 A038594 A038595 * A038597 A038598 A038599

Keyword

nonn

Author

Jeff Burch

Extensions

More terms from Jud McCranie

Status

approved