A136766 a(n) = leading digit of n! in base 16.

1, 1, 2, 6, 1, 7, 2, 1, 9, 5, 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 5, 8, 12, 1, 2, 3, 6, 13, 1, 3, 6, 13, 1, 4, 9, 1, 3, 8, 1, 3, 10, 1, 4, 14, 2, 7, 1, 4, 14, 2, 9, 2, 7, 1, 5, 1, 4, 1, 4, 1, 3, 15, 4, 1, 4, 1, 5, 1, 6, 1, 7, 2, 10, 3, 15, 4, 1, 7, 2, 11, 3, 1, 6, 2, 11, 4, 1, 7, 2, 1, 5, 2, 12, 4, 1, 11

Offset

0,3

Links

David A. Corneth, Table of n, a(n) for n = 0..9999 (first 1001 terms from Robert G. Wilson v)

Example

For n=5, 5! = 5*4*3*2*1 = 120 in base 10, which is 78 in hexadecimal (7*16 + 8*1), so a(5) = 7. - Michael B. Porter, Sep 20 2016

Mathematica

Array[ IntegerDigits[#!, 16][[1]] &, 1001, 0] (* Robert G. Wilson v, Sep 20 2016 *)
Table[Floor[#/16^Floor@ Log[16, #]] &[n!], {n, 0, 98}] (* Michael De Vlieger, Sep 20 2016 *)

Prog

(PARI) a(n) = digits(n!, 16)[1]; \\ Michel Marcus, Jan 27 2015

Crossrefs

Cf. A000142, A136702, A136754, A136755, A136756, A136757, A136758, A136759, A136760, A008905, A136761, A136762, A136763, A136764, A136765.

Sequence in context: A019576 A141906 A352125 * A199501 A021386 A201936

Adjacent sequences: A136763 A136764 A136765 * A136767 A136768 A136769

Keyword

nonn,easy,base

Author

Carl R. White, Jan 21 2008

Status

approved