A081779 Ordered m for which m = k^3*a*b*(a^4 - b^4) determine (unique) solution triples(k,a,b), where k=1,2,3,... and (a,b) are coprime pairs, not both odd (i.e., of opposite parity).

30, 240, 390, 810, 1020, 1920, 2100, 3120, 3750, 6090, 6480, 7380, 7770, 8160, 10290, 10530, 15360, 16800, 20130, 21870, 24960, 27540, 30000, 32760, 33390, 39930, 46410, 48720, 48750, 51840, 56700, 59040, 60060, 62160, 65280, 65910, 82320, 84240, 94920, 96360

Offset

1,1

Comments

Also called Saint-Exupery numbers.

Links

Table of n, a(n) for n=1..40.

N. des Vallieres and F. D'Agay, Le Probleme du Pharaon.

Formula

a(n) = A057096(n)/2.

Mathematica

Import["https://oeis.org/A057096/b057096.txt", "Table"][[;; 40, 2]]/2 (* Jean-François Alcover, Nov 21 2019 *)

Crossrefs

Cf. A057096.

Sequence in context: A190068 A339750 A196412 * A069487 A008385 A061167

Adjacent sequences: A081776 A081777 A081778 * A081780 A081781 A081782

Keyword

nice,nonn

Author

Lekraj Beedassy, Apr 10 2003

Extensions

Corrected and extended by Jean-François Alcover, Nov 21 2019

Status

approved