A261175 - OEIS

%I #33 Jan 10 2022 15:43:20

%S 1,1,1,3,5,8,13,19,26,35,45,56,69,84,100,117,137,158,180,204,231,258,

%T 288,319,352,387,424,463,503,546,590,636,684,734,786,840,897,955,1015,

%U 1077,1141,1207,1275,1345,1418,1492,1568,1647,1728,1811,1896,1983,2072,2163,2257,2352

%N Number of digits of Hyperfactorial(n).

%H Chai Wah Wu, <a href="/A261175/b261175.txt">Table of n, a(n) for n = 0..1000</a>

%F a(n) = 1 + floor( log_10( A002109(n))) = A055642(A002109(n)).

%t Table[1 + Floor@ Log10@ Hyperfactorial@ n, {n, 0, 55}]

%o (PARI) a(n)=my(r=1);for(i=1,n+1,r *= i^i);floor(log(r)/log(10))+1 \\ _Anders Hellström_, Aug 20 2015

%o (PARI) vector(60, n, n--; #Str(prod(k=2, n, k^k))) \\ _Michel Marcus_, Aug 20 2015

%o (Python)

%o A261175_list, n = [], 1

%o for i in range(100):

%o     n *= i**i

%o     A261175_list.append(len(str(n)))  # _Chai Wah Wu_, Aug 21 2015

%Y Cf. A002109, A061010, A260262.

%K nonn

%O 0,4

%A _Robert G. Wilson v_, Aug 20 2015