A318955 Binomial(A319500(n),a(n)) = A006917(n) with 2 <= a(n) <= A319500(n)/2.

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, 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, 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

Offset: 1

Author

Robert Israel, Sep 20 2018

Keywords

• nonn

Comments

First differs from A022912 at n=18.

Examples

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

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A006987, A022912, A319500.

Programs

Maple

N:= 10000: # for binomial(n, k) values <= N
S:= {}:
for n from 2 while n*(n-1)/2 <= N do
  for k from 2 to n/2 do
    v:= binomial(n, k);
    if v > N then break fi;
    if not member(v,S) then
      S:= S union {v};
      K[v]:= k;
    fi
od od:
A006987:= sort(convert(S,list)):
seq(K[A006987[i]],i=1..nops(A006987));