A132329 Numbers that cannot be expressed as the difference of the squares of primes.
1, 2, 3, 4, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, 42, 43, 44, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 80
Offset: 1
Keywords
Programs
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Mathematica
lim=80;sp={4};i=2;Until[Prime[i]^2-(Prime[i]-2)^2>lim,AppendTo[sp,Prime[i]^2];i++];Complement[Range[lim],Union[Differences/@Subsets[sp,{2}]//Flatten]] (* James C. McMahon, Mar 08 2025 *)
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