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A002338
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x such that p = (x^2 + 27y^2 )/4.
(Formerly M3754 N1531)
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2
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1, 5, 7, 4, 11, 8, 1, 5, 7, 17, 19, 13, 2, 20, 23, 19, 14, 25, 7, 23, 11, 13, 28, 22, 17, 29, 26, 32, 16, 35, 1, 5, 37, 35, 13, 29, 34, 31, 19, 2, 28, 10, 23, 25, 32, 43, 29, 1, 31, 11, 26, 49, 47, 17, 43, 40, 49, 37, 8, 53, 44, 50, 16, 41, 29, 49, 31, 56, 5, 7, 35, 13, 59, 47, 19, 52, 61, 41, 61, 10, 43, 14, 53, 59, 64, 65, 62, 55, 22, 65, 35, 67, 7
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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REFERENCES
| A. J. C. Cunningham, Quadratic Partitions. Hodgson, London, 1904, p. 1.
B. Engquist and Wilfried Schmid, Mathematics Unlimited - 2001 and Beyond, Chapter on Error-correcting codes and curves over finite fields, see pp. 1118-1119. [From Neven Juric, Oct 16 2008.]
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).
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LINKS
| Ruperto Corso, Table of n, a(n) for n=1..1000
S. R. Finch, Powers of Euler's q-Series, (arXiv:math.NT/0701251).
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PROG
| (PARI) forprime(p=2, 10000, for(x=1, floor(2*sqrt(p)), px=4*p-x^2; if(px%27==0, if(issquare(px/27, &y), print1(x", "))))) /* Ruperto Corso, Dec 14 2011 */
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CROSSREFS
| Cf. A002339.
Sequence in context: A096437 A096458 A123489 * A178668 A198744 A201944
Adjacent sequences: A002335 A002336 A002337 * A002339 A002340 A002341
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| Corrected and extended by Ruperto Corso (rupertocorsoto(AT)gmail.com), Dec 14 2011
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