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%I #10 Dec 11 2013 09:29:18
%S 2,2,2,2,6,2,2,4,6,4,4,6,2,2,12,10,4,10,6,6,6,8,2,2,12,10,6,6,2,2,10,
%T 4,14,12,4,4,10,4,6,2,6,4,10,10,12,6,4,14,6,4,10,12,8,4,6,24,10,6,2,8,
%U 14,18,2,6,2,12,16,4,6,6,2,6,26,2,8,10,4,10,4
%N a(n) = prime(1+prime(n)) - prime(prime(n)).
%C Number of entries in {x,..} such that PrimePi[x]=Prime[n].
%F a(n) = Card{x; A000720(x) = A000040(n)}.
%F a(n) = A072677(n) - A006450(n).
%e n = 25: p(25) = 97, Pi[x] = 97 holds for 12 numbers: X = {509, 510, 511, 512, 513, 514, 515, 516, 517, 518, 519, 520} so a(25) = 12. Largest 520 = A073123(25), smallest = A006450(25).
%t Table[Prime[Prime[n]+1]-Prime[Prime[n]], {n, 1, 256}]
%o (PARI) a(n) = prime(1+prime(n)) - prime(prime(n)); \\ _Michel Marcus_, Dec 11 2013
%Y Cf. A000720, A000040, A006450, A072677, A073123.
%K nonn
%O 1,1
%A _Labos Elemer_, Jul 16 2002
%E More terms from _Michel Marcus_, Dec 11 2013
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