A261175 Number of digits of Hyperfactorial(n).

1, 1, 1, 3, 5, 8, 13, 19, 26, 35, 45, 56, 69, 84, 100, 117, 137, 158, 180, 204, 231, 258, 288, 319, 352, 387, 424, 463, 503, 546, 590, 636, 684, 734, 786, 840, 897, 955, 1015, 1077, 1141, 1207, 1275, 1345, 1418, 1492, 1568, 1647, 1728, 1811, 1896, 1983, 2072, 2163, 2257, 2352

Offset

0,4

Links

Chai Wah Wu, Table of n, a(n) for n = 0..1000

Formula

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

Mathematica

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

Prog

(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
(PARI) vector(60, n, n--; #Str(prod(k=2, n, k^k))) \\ Michel Marcus, Aug 20 2015
(Python)
A261175_list, n = [], 1
for i in range(100):
    n *= i**i
    A261175_list.append(len(str(n)))  # Chai Wah Wu, Aug 21 2015

Crossrefs

Cf. A002109, A061010, A260262.

Sequence in context: A175388 A310037 A104563 * A265064 A030762 A023500

Adjacent sequences: A261172 A261173 A261174 * A261176 A261177 A261178

Keyword

nonn

Author

Robert G. Wilson v, Aug 20 2015

Status

approved