A262724 Triangular numbers representable as 3^x + y^3.

1, 3, 10, 28, 36, 91, 1081, 2278, 2926, 8001, 46665, 5639761, 10911456, 166066200, 341532180, 3137785371, 1647882316985625, 875366737297292691171, 465198187808352499674075441

Offset

1,2

Comments

Any further terms are greater than 10^30. - Charles R Greathouse IV, Oct 02 2015

Links

Table of n, a(n) for n=1..19.

Prog

(PARI) list(lim)=my(v=List(), X, t); for(x=0, logint(lim\=1, 3), X=3^x; for(y=0, sqrtnint(lim-X, 3), if(ispolygonal(t=X+y^3, 3), listput(v, t)))); Set(v) \\ Charles R Greathouse IV, Sep 28 2015

Crossrefs

Cf. A000217, A225390, A226499, A227027, A259745, A259746, A262242, A262251.

Sequence in context: A279136 A127912 A005956 * A059193 A226863 A325793

Adjacent sequences: A262721 A262722 A262723 * A262725 A262726 A262727

Keyword

nonn,hard

Author

Alex Ratushnyak, Sep 28 2015

Extensions

a(17)-a(19) from Charles R Greathouse IV, Sep 28 2015

Status

approved