A002341 Numbers y such that p = x^2 - 5y^2, where p = 0, 1, or 4 (mod 5). (Formerly M0136 N0054)

2, 1, 3, 2, 1, 4, 1, 2, 5, 7, 4, 2, 6, 5, 1, 2, 3, 11, 6, 1, 5, 3, 10, 7, 12, 1, 2, 9, 4, 13, 7, 6, 5, 9, 14, 16, 8, 11, 2, 7, 3, 4, 10, 1, 17, 19, 2, 8, 14, 16, 1, 13, 20, 9, 3, 8, 5, 6, 11, 14

Offset

1,1

References

A. J. C. Cunningham, Quadratic Partitions. Hodgson, London, 1904, p. 1.

D. H. Lehmer, Guide to Tables in the Theory of Numbers. Bulletin No. 105, National Research Council, Washington, DC, 1941, p. 55.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=1..60.

A. J. C. Cunningham, Quadratic Partitions, Hodgson, London, 1904 [Annotated scans of selected pages]

Crossrefs

Cf. A002340.

Sequence in context: A098896 A108371 A138530 * A348888 A128260 A083368

Adjacent sequences: A002338 A002339 A002340 * A002342 A002343 A002344

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Offset corrected by Mohammed Yaseen, Jul 24 2023

Status

approved