A238120 Powerful numbers of the form x^3 + y^3 with x and y coprime.

9, 3528, 12168, 51984, 207576, 450241, 711828, 798768, 1590121, 7154784, 8609599, 40589641, 95355225, 138393792, 244293408, 344157184, 726887051, 737461269, 1232922769, 1290821184, 1630544400, 1734139449, 2901360600, 3002319675, 3401256943, 4435426801, 4589212453

Offset

1,1

Comments

Powerful numbers are n such that p | n -> p^2 | n for all primes p, see A001694.

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..150

Prog

(PARI) list(lim)=my(v=List(), x3, t); for(x=1, sqrtnint(lim\1-1, 3), x3=x^3; for(y=1, x, if(gcd(x, y)>1, next); t=x3+y^3; if(t>lim, break); if(ispowerful(t), listput(v, t)))); Set(v)

Crossrefs

Cf. A001694.

Sequence in context: A234145 A291547 A266458 * A229151 A162013 A222948

Adjacent sequences: A238117 A238118 A238119 * A238121 A238122 A238123

Keyword

nonn

Author

Charles R Greathouse IV, Feb 17 2014

Status

approved