A119628 Inverse permutation to sequence A083872.

1, 2, 3, 5, 9, 4, 31, 6, 17, 10, 271, 7, 793, 32, 11, 18, 5377, 19, 14689, 12, 33, 272, 96001, 8, 161, 794, 97, 34, 917281, 13, 2332801, 61, 273, 5378, 35, 20, 19595521, 14690, 795, 14, 102435841, 36, 258048001, 274, 21, 96002, 1258709761, 22, 1585, 162, 5379

Offset: 1

Author

Leroy Quet, Jun 08 2006

Keywords

• nonn

Links

• Rémy Sigrist, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A027423, A083872.

Programs

PARI

{m=31;v=[];for(n=1,m,v=concat(v,vecsort(eval(setminus(Set(divisors(n!)),Set(v))))));z=100;u=vector(z);for(j=1,#v,if(v[j]<=z,u[v[j]]=j));i=1;while(u[i]>0,print1(u[i],",");i++)} \\ Klaus Brockhaus, Aug 16 2006

PARI

a(n) = my (ff=1, f=1); for (i=1, oo, f*=i; if (f%n==0, return (numdiv(ff) + sum(j=1, n, ff%j!=0 && f%j == 0))); ff=f) \\ Rémy Sigrist, Nov 08 2018

Formula

a(p) = A027423(p-1) + 1 for any prime number p. - Rémy Sigrist, Nov 08 2018

Extensions

a(11) to a(36) from Klaus Brockhaus, Aug 16 2006

More terms from Rémy Sigrist, Nov 08 2018