A318955 - OEIS

%I #11 Sep 21 2018 22:37:00

%S 2,2,2,3,2,2,3,2,2,2,3,2,4,2,3,2,2,3,4,2,2,3,2,2,4,3,2,5,2,2,3,2,2,4,

%T 2,3,2,2,2,3,5,2,4,2,2,3,2,2,2,2,3,2,4,2,2,5,3,2,2,2,6,2,3,2,4,2,2,2,

%U 3,2,2,2,5,2,3,4,2,2,2,3,2,2,2,6,2,3,4,2,2,2,5,2,3,2,2,2,2,3,2

%N Binomial(A319500(n),a(n)) = A006917(n) with 2 <= a(n) <= A319500(n)/2.

%C First differs from A022912 at n=18.

%H Robert Israel, <a href="/A318955/b318955.txt">Table of n, a(n) for n = 1..10000</a>

%e a(3) = 6 because A006987(3) = 15 = binomial(6,2).

%p N:= 10000: # for binomial(n, k) values <= N

%p S:= {}:

%p for n from 2 while n*(n-1)/2 <= N do

%p   for k from 2 to n/2 do

%p     v:= binomial(n, k);

%p     if v > N then break fi;

%p     if not member(v,S) then

%p       S:= S union {v};

%p       K[v]:= k;

%p     fi

%p od od:

%p A006987:= sort(convert(S,list)):

%p seq(K[A006987[i]],i=1..nops(A006987));

%Y Cf. A006987, A022912, A319500.

%K nonn

%O 1,1

%A _Robert Israel_, Sep 20 2018