1,1

L. E. Dickson, History of The Theory of Numbers, Vol. 2 pp. 644-7, Chelsea NY 1923

R. K. Guy, Unsolved Problems in Number Theory, D1.

J. Leech, Some solutions of Diophantine equations, Proc. Camb. Phil. Soc., 53 (1957), 778-780.

E. Rosenstiel et al., The four least solutions ..., Bull. Inst. App. Math., vol. 27, 1991, pp. 155-157.

D. J. Bernstein, List of 516 primitive solutions p^4 + q^4 = r^4 + s^4 = a(n)

D. J. Bernstein, Enumerating solutions to p(a) + q(b) = r(c) + s(d)

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

Carlos Rivera, Puzzle 103

Cf. A018786.

Sequence in context: A145277 A123705 A018786 this_sequence A105382 A032432 A035795

Adjacent sequences: A003821 A003822 A003823 this_sequence A003825 A003826 A003827

nonn

N. J. A. Sloane (njas(AT)research.att.com).

More terms from David W. Wilson Aug 15 1996.