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Indices of squares (of semiprimes) in the 4-almost primes.
2

%I #2 Mar 30 2012 17:36:44

%S 1,3,8,12,24,29,59,66,90,97,162,172,187,224,234,335,385,412,489,531,

%T 551,630,692,791,921,997,1128,1223,1256,1285,1420,1484,1518,1549,1937,

%U 2146,2315,2441,2483,2556,2606,2651,2915,3124,3175,3542,3587,3645,3751,3800

%N Indices of squares (of semiprimes) in the 4-almost primes.

%C A014613(a(n)) = A074985(n) = A001358(n)^2.

%e a(5) = 24 as 196=14^2=semiprime(5)^2, the 5th square in the 4-almost primes, is the 24th 4-almost prime.

%Y Cf. A128302, A014613, A074985, A001358, A128304.

%K nonn

%O 1,2

%A _Rick L. Shepherd_, Mar 04 2007