A081779 - OEIS

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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).

1

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

(list; graph; refs; listen; history; text; internal format)

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

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