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A322158 a(n) is the smallest m for which binomial(m,5) has exactly n distinct prime factors. 0

%I #23 Jan 04 2019 04:08:38

%S 6,9,11,22,25,70,78,276,497,990,1771,8178,20504,44254,181051,416328,

%T 1013728,3383579,8667726,34332376,122289552,244215150,969751302,

%U 1865174676,6648863728,26888317326,107132035803

%N a(n) is the smallest m for which binomial(m,5) has exactly n distinct prime factors.

%C Binomial(m,5) is never prime, so the offset is 2.

%t a[n_] := Module[{m = 5}, While[PrimeNu[Binomial[m, 5]] != n, m++]; m]; Array[a, 10, 2] (* _Amiram Eldar_, Nov 29 2018 *)

%o (PARI) a(n) = for(m=5, oo, if(omega(binomial(m, 5))==n, return(m))) \\ _Felix Fröhlich_, Dec 01 2018

%Y Cf. A005733, A005735, A321852.

%K nonn,more

%O 2,1

%A _Zachary M Franco_, Nov 27 2018

%E a(22)-a(23) from _Chai Wah Wu_, Dec 29 2018

%E a(24)-a(28) from _Giovanni Resta_, Jan 04 2019

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Last modified May 1 20:04 EDT 2024. Contains 372176 sequences. (Running on oeis4.)