A103512 Smallest m such that A001147(n)+m is prime.
1, 2, 2, 2, 2, 4, 16, 8, 4, 64, 2, 2, 8, 2, 4, 118, 32, 82, 178, 4, 8, 4, 16, 16, 298, 64, 16, 194, 2, 298, 316, 8, 334, 32, 226, 386, 4, 2, 358, 8, 178, 254, 206, 206, 218, 8, 4, 254, 452, 914, 346, 2, 758, 394, 362, 394, 556, 422, 32, 346, 1108, 394, 932, 362, 604, 1382
Offset: 1
Keywords
Examples
A001147(1)=1!!=1, 1+1=2 is prime, so a(1)=1; A001147(2)=3!!=3, 3+2=5 is prime, so a(2)=2; A001147(7)=13!!=135135, 135135+16=135151 is prime, so a(7)=16.
Programs
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Mathematica
Flatten[Table[Select[Range[1500],PrimeQ[(2n-1)!!+#]&,1],{n,66}]] (* James C. McMahon, Jan 20 2024 *)