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, 26, 15526, 151165506068

Offset

1,1

Links

Table of n, a(n) for n=1..4.

Example

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).

Mathematica

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]

Crossrefs

Cf. A001222, A273380.

Sequence in context: A134795 A268667 A330032 * A094680 A259326 A061192

Adjacent sequences: A273378 A273379 A273380 * A273382 A273383 A273384

Keyword

nonn,more

Author

Giovanni Resta, May 21 2016

Status

approved