A332842 Initial digit of n-th superfactorial.

1, 1, 2, 1, 2, 3, 2, 1, 5, 1, 6, 2, 1, 7, 6, 9, 1, 6, 4, 5, 1, 6, 7, 1, 1, 1, 7, 7, 2, 2, 5, 4, 1, 1, 3, 3, 1, 1, 8, 1, 1, 4, 6, 4, 1, 1, 7, 1, 2, 1, 4, 6, 5, 2, 5, 6, 4, 1, 4, 6, 5, 2, 8, 1, 2, 1, 9, 3, 8, 1, 1, 1, 9, 4, 1, 3, 6, 9, 1, 9, 6, 3, 1, 7, 2, 6, 1, 3, 6, 1, 1, 2, 2, 3, 3, 3, 3, 3, 3, 2, 2

Offset

0,3

Links

Chai Wah Wu, Table of n, a(n) for n = 0..10000

Formula

a(n) = A000030(A000178(n)).

Example

a(6) = 2 because A000178(6) = 24883200.

Prog

(PARI) a(n) = digits(prod(k=2, n, k!))[1]; \\ Michel Marcus, Feb 26 2020
(Python)
def A332842(n):
    m, k = 1, 1
    for i in range(2, n+1):
        k *= i
        m *= k
    return int(str(m)[0]) # Chai Wah Wu, Mar 17 2020

Crossrefs

Cf. A000030, A000178, A008905.

Sequence in context: A336157 A190167 A339010 * A352696 A171565 A328266

Adjacent sequences: A332839 A332840 A332841 * A332843 A332844 A332845

Keyword

easy,nonn,base

Author

Eder Vanzei, Feb 26 2020

Status

approved