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Search: id:A133676
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| A133676 |
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Negative discriminants with form class group of exponent 4 (negated). |
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+0
1
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| 39, 55, 56, 63, 68, 80, 128, 136, 144, 155, 156, 171, 184, 196, 203, 208, 219, 220, 224, 252, 256, 259, 260, 264, 275, 276, 291, 292, 308, 320, 323, 328, 336, 355, 360, 363, 384, 387, 388, 400, 456, 468, 475, 504, 507, 528, 544, 552, 564, 568, 576, 580, 592
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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The sequence is finite. It appears to have exactly 485 terms, the largest being 887040.
The finiteness of the sequence was proved by Earnest and Estes.
I found the 485 terms with PARI and didn't find any other up to 50000000.
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REFERENCES
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David Brink, Five peculiar theorems on simultaneous representation of primes by quadratic forms. J. Number Theory, 2008, to appear.
A. G. Earnest and D. R. Estes, An algebraic approach to the growth of class numbers of binary quadratic lattices, Mathematika 28 (1981), no. 2, 160--168.
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LINKS
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David Brink, Table of n, a(n) for n = 1..485
David Brink, Five peculiar theorems on simultaneous representation of primes by quadratic forms (Video abstract)
Journal of Number Theory, Video Abstracts
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CROSSREFS
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Sequence in context: A053181 A020305 A070145 this_sequence A013658 A165346 A063480
Adjacent sequences: A133673 A133674 A133675 this_sequence A133677 A133678 A133679
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KEYWORD
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fini,nonn
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AUTHOR
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David Brink (brink(AT)math.ku.dk), Dec 29 2007
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