A259182 a(n) = prime(n) if n prime otherwise 1.
1, 3, 5, 1, 11, 1, 17, 1, 1, 1, 31, 1, 41, 1, 1, 1, 59, 1, 67, 1, 1, 1, 83, 1, 1, 1, 1, 1, 109, 1, 127, 1, 1, 1, 1, 1, 157, 1, 1, 1, 179, 1, 191, 1, 1, 1, 211, 1, 1, 1, 1, 1, 241, 1, 1, 1, 1, 1, 277, 1, 283, 1, 1, 1, 1, 1, 331, 1, 1, 1, 353, 1, 367, 1, 1, 1, 1
Offset: 1
Examples
a(7) = 17 because prime(7) = 17 is prime. a(8) = 1 because 8 is not prime.
Programs
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Magma
[IsPrime(n) select NthPrime(n) else 1: n in [1..100]];
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Mathematica
Table[If[! PrimeQ[n], 1, Prime[n]], {n, 100}]
Comments