A268063 Primes of the form (k^3 - k^2 - k - 1)/2 for some integer k > 0.
7, 47, 599, 1567, 5807, 7487, 9463, 20807, 24623, 28879, 33599, 81647, 111599, 123007, 161839, 225263, 262399, 282407, 397807, 541007, 573247, 606743, 641519, 922807, 1115399, 1513727, 1577383, 1709999, 1779007, 1849847, 1997119, 2399039, 2573807, 2948399
Offset: 1
Examples
k=15: (15^3 - 15^2 - 15 - 1)/2 = 1567 (is prime).
Links
- G. C. Greubel, Table of n, a(n) for n = 1..3240
Programs
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Magma
[a: n in [0..200] | IsPrime(a) where a is (n^3-n^2-n-1) div 2 ]; // Vincenzo Librandi, Jan 26 2016
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Mathematica
Select[Table[(n^3 - n^2 - n - 1) / 2, {n, 200}], PrimeQ] (* Vincenzo Librandi, Jan 26 2016 *) -
PARI
lista(nn) = for(n=1, nn, if(ispseudoprime(p=4*n^3+4*n^2-1), print1(p, ", "))); \\ Altug Alkan, Mar 14 2016
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Sage
[(k^3-k^2-k-1)/2 for k in [2*i+1 for i in [1..100]] if is_prime(Integer((k^3-k^2-k-1)/2))] # Tom Edgar, Jan 25 2016
Extensions
More terms from Tom Edgar, Jan 25 2016
Comments