A178660 Numbers k such that k^3 +- (k+5)^2 are primes.
7, 12, 13, 18, 58, 142, 187, 502, 597, 657, 702, 907, 912, 942, 943, 972, 1057, 1168, 1248, 1357, 1453, 1533, 1663, 1938, 2013, 2088, 2272, 2373, 2478, 2608, 2848, 2968, 3003, 3028, 3108, 3247, 3423, 3478, 3583, 3817, 3927, 3957, 4132, 4212, 4632, 4668
Offset: 1
Keywords
Examples
7 is a term since: 7^3 +- 12^2 -> (199,487) which are primes.
Links
- G. C. Greubel, Table of n, a(n) for n = 1..10000
Programs
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Mathematica
Select[Range[8! ],PrimeQ[ #^3-(#+5)^2]&&PrimeQ[ #^3+(#+5)^2]&] Select[Range[4700],AllTrue[#^3+{(#+5)^2,-(#+5)^2},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Mar 19 2018 *)