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 A273381 2..a(n) is the smallest range in which the most common value of Omega(k) is n, where Omega(k) is the number of prime factors of k (A001222). 2

%I #4 May 21 2016 14:22:13

%S 2,26,15526,151165506068

%N 2..a(n) is the smallest range in which the most common value of Omega(k) is n, where Omega(k) is the number of prime factors of k (A001222).

%e Among the numbers from 2 to a(2)=26 the most common value of Omega is 2. Indeed, there are 9 numbers for which Omega is 1 (the primes) and 10 for which Omega is 2 (the semiprimes).

%t a[n_] := Block[{c1=0, c2=0, v, k=1}, While[c2<=c1, v=PrimeOmega[++k]; If[v == n-1, c1++]; If[v == n, c2++]]; k]; Array[a, 3]

%Y Cf. A001222, A273380.

%K nonn,more

%O 1,1

%A _Giovanni Resta_, May 21 2016

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Last modified April 13 10:11 EDT 2024. Contains 371640 sequences. (Running on oeis4.)