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

6, 9, 11, 22, 25, 70, 78, 276, 497, 990, 1771, 8178, 20504, 44254, 181051, 416328, 1013728, 3383579, 8667726, 34332376, 122289552, 244215150, 969751302, 1865174676, 6648863728, 26888317326, 107132035803

Offset

2,1

Comments

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

Links

Table of n, a(n) for n=2..28.

Mathematica

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

Prog

(PARI) a(n) = for(m=5, oo, if(omega(binomial(m, 5))==n, return(m))) \\ Felix Fröhlich, Dec 01 2018

Crossrefs

Cf. A005733, A005735, A321852.

Sequence in context: A084418 A226133 A125971 * A143710 A087022 A315951

Adjacent sequences: A322155 A322156 A322157 * A322159 A322160 A322161

Keyword

nonn,more

Author

Zachary M Franco, Nov 27 2018

Extensions

a(22)-a(23) from Chai Wah Wu, Dec 29 2018

a(24)-a(28) from Giovanni Resta, Jan 04 2019

Status

approved