A049110 Number of divisors of A006601(n).

6, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 12, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 12, 8, 8, 8, 8, 8, 12, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8

Offset: 1

Author

Olivier Gérard

Keywords

• nonn

Links

• Antti Karttunen, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000005, A006601.

Programs

Mathematica

With[{s = DivisorSigma[0, Range[10^5]]}, s[[SequencePosition[s, {x_, x_, x_, x_}][[All, 1]] ]] ] (* Michael De Vlieger, Nov 07 2018, after Harvey P. Dale at A006601 *)

PARI

up_to = 10000;
A049110list(up_to) = { my(v=vector(up_to),t,n=1,i=0); while(iA049110list(up_to);
A049110(n) = v049110[n]; \\ Antti Karttunen, Nov 07 2018

PARI

upto(n) = my(res = List(), current = 1, c, streak = 1); for(i = 2, n + 3, c = numdiv(i); if(c == current, streak++; if(streak == 4, listput(res, c)), streak = 1; current = c)); res \\ David A. Corneth, Nov 07 2018

Formula

a(n) = A000005(A006601(n)).