A336069 - OEIS

%I #6 Jul 08 2020 05:09:11

%S 2,8,7,1,0,6,1,3,1,8,6,6,3,4,7,1,7,3,2,2,2,8,6,1,0,3,8,3,0,0,4,9,5,5,

%T 1,0,5,9,1,4,4,3,8,1,2,3,0,9,3,8,8,9,0,6,1,0,5,5,9,2,6,9,5,7,1,0,3,8,

%U 1,4,2,1,3,2,1,0,9,1,2,0,9,0,1,9,0,3,4

%N Decimal expansion of the asymptotic density of numbers k divisible by A007949(k) (A336068).

%H Tibor Šalát, <a href="https://dml.cz/handle/10338.dmlcz/129777">On the function a_p, p^a_p(n) || n (n > 1)</a>, Mathematica Slovaca, Vol. 44, No. 2 (1994), pp. 143-151.

%F Equals 2 * Sum_{k>=1} 1/(k * 3^(k - A007949(k) + 1)).

%e 0.287106131866347173222861038300495510591443812309388...

%t RealDigits[2 * Sum[1/k/3^(k + 1 - IntegerExponent[k, 3]), {k, 1, 1000}], 10, 100][[1]]

%Y Cf. A007949, A336067, A336068.

%K nonn,cons

%O 0,1

%A _Amiram Eldar_, Jul 07 2020