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%I #8 Dec 23 2012 23:44:06
%S 1,2,4,6,8,10,14,17,22,28,35,43,53,65,78,93,111,129,153,179,210,245,
%T 285,328,381,441,508,582,668,764,870,990,1123,1270,1436,1625,1825,
%U 2054,2309,2590,2904,3246,3631,4052,4512,5022,5582,6197,6872,7612,8421,9312
%N a(n+1) is equal to a(n) plus the number of primes between a(n) and 2*a(n) inclusively.
%H Robert G. Wilson v, <a href="/A220850/b220850.txt">Table of n, a(n) for n = 1..558</a>
%e a(6) = the number of primes between a(5) and 2*a(5) plus a(5) = the number of primes [8, 16] + 8 = 2 + 8 = 10.
%t f[n_] := PrimePi[ 2n] - PrimePi[n - 1]; NestList[# +f@# &, 1, 50]
%Y Cf. A035250, A220851, inspired by A084140.
%K easy,nonn
%O 1,2
%A _Robert G. Wilson v_, Dec 22 2012