A344376 Numbers that are both octagonal numbers (A000567) and octagonal pyramidal numbers (A002414).

0, 1, 1045, 5985, 123395663059845, 774611255177760

Offset

1,3

Comments

Terms correspond to integral points on an elliptic curve, which allows all of them to be found efficiently. - Max Alekseyev, Feb 19 2024

Links

Table of n, a(n) for n=1..6.

Prog

(PARI) for(k=0, 1e5, if(ispolygonal(m=k*(k+1)*(2*k-1)/2, 8), print1(m", ")))

Crossrefs

Intersection of A000567 and A002414.

Cf. A027568, A334012.

Sequence in context: A345767 A324320 A334012 * A023067 A344410 A110597

Adjacent sequences: A344373 A344374 A344375 * A344377 A344378 A344379

Keyword

nonn,fini,full

Author

Seiichi Manyama, May 16 2021

Extensions

Keywords 'fini' and 'full' added by Max Alekseyev, Feb 19 2024

Status

approved