login
Number of times n appears in a 10 X 10 multiplication table.
1

%I #7 Oct 27 2019 22:12:42

%S 1,2,2,3,2,4,2,4,3,4,0,4,0,2,2,3,0,4,0,4,2,0,0,4,1,0,2,2,0,4,0,2,0,0,

%T 2,3,0,0,0,4,0,2,0,0,2,0,0,2,1,2,0,0,0,2,0,2,0,0,0,2,0,0,2,1,0,0,0,0,

%U 0,2,0,2,0,0,0,0,0,0,0,2,1,0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,1

%N Number of times n appears in a 10 X 10 multiplication table.

%C Identical to A000005(n) for n <= 10.

%F a(n) = 0 for n > 100.

%e a(2)=2 because the number 2 appears in 2 cells in a 10 X 10 multiplication table.

%t nn = 10; mtab = Flatten[Table[i*j, {i, nn}, {j, nn}]]; Table[Count[mtab, n], {n, 100}]

%Y First few terms are identical to A000005, A179941, A179942.

%K nonn

%O 1,2

%A _Dominick Cancilla_, Aug 02 2010

%E Extended by _T. D. Noe_, Mar 24 2011