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Search: id:A097823
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| A097823 |
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Numbers n such that n^2+n+41 (Euler's "prime generating polynomial") is not square-free. |
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+0
2
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| 40, 603, 798, 890, 917, 1245, 1253, 1318, 1640, 1651, 1721, 2010, 2069, 2251, 2452, 2606, 2649, 3094, 3099, 3321, 3402, 3527, 3607, 4123, 4239, 4301, 4819, 4943, 5002, 5083, 5308, 5372, 5425, 5736, 5790, 5930, 5958, 5998, 6150, 6416, 6511, 6683, 6764
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Eric Weisstein's World of Mathematics, Prime-Generating Polynomial
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EXAMPLE
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a(1)=40: p(40)=40^2+40+41=1681=41^2, a(2)=603: p(603)=364253=197*43^2, a(11)=1721: p(1721)=2963603=43*41^3, a(68)=10428: p(10428)=108753653=743^2*197, a(91)=14144: p(14144)=200066921=47^4*41.
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CROSSREFS
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Cf. A013929 n is not square-free, A002837 n such that n^2-n+41 is prime, A007634 n such that n^2+n+41 is composite, A005846 primes of form n^2+n+41, A097822 n^2+n+41 has more than 2 prime factors.
Sequence in context: A109105 A107419 A159946 this_sequence A002847 A057808 A160445
Adjacent sequences: A097820 A097821 A097822 this_sequence A097824 A097825 A097826
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KEYWORD
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nonn
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AUTHOR
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Hugo Pfoertner (hugo(AT)pfoertner.org), Aug 26 2004
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