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

1,1

Links

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

Formula

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

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 *)

Prog

(PARI)
up_to = 10000;
A049110list(up_to) = { my(v=vector(up_to), t, n=1, i=0); while(i<up_to, t = numdiv(n); if(numdiv(n+1)==t && numdiv(n+2)==t && numdiv(n+3)==t, i++; v[i] = t); n++); (v); }
v049110 = A049110list(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

Crossrefs

Cf. A000005, A006601.

Sequence in context: A157683 A300897 A346289 * A136050 A281112 A229020

Adjacent sequences: A049107 A049108 A049109 * A049111 A049112 A049113

Keyword

nonn

Author

Olivier Gérard

Status

approved