cp's OEIS Frontend

A256491 a(n) = prime(prime(n) + n - 2).

%I A256491 #17 Nov 21 2018 02:29:48
%S A256491 2,5,13,23,43,59,79,97,113,157,173,211,239,257,281,331,373,389,433,
%T A256491 461,479,523,569,607,659,691,719,751,769,811,911,947,997,1019,1091,
%U A256491 1103,1163,1217,1249,1297,1361,1381,1459,1483,1511,1543,1619,1723,1759,1787,1831
%N A256491 a(n) = prime(prime(n) + n - 2).
%C A256491 All terms are prime.
%F A256491 a(n) = A256464(prime(n)).
%e A256491 a(3) = prime(prime(3) + 3 - 2) = prime(5 + 3 - 2) = prime(6) = 13.
%e A256491 a(4) = prime(prime(4) + 4 - 2) = prime(7 + 4 - 2) = prime(9) = 23.
%e A256491 a(5) = prime(prime(5) + 4 - 2) = prime(11 + 4 - 2) = prime(13) = 43.
%t A256491 Table[Prime[Prime[n] + n - 2], {n, 51}] (* _Jon Maiga_, Nov 20 2018 *)
%o A256491 (PARI) a(n) = {i = prime(n); stop = 0; while (! stop, vab = vector(i, k, sigma(k)/k); w = vecsort(vab, , 1); pos = posv(n, w); if (pos == n, stop=1, i++);); i;}
%Y A256491 Cf. A256464.
%K A256491 nonn
%O A256491 1,1
%A A256491 _Michel Marcus_, Mar 30 2015
%E A256491 Name clarified by _Alonso del Arte_, Nov 20 2018, was "A256464(prime(n))."