OFFSET
3,1
COMMENTS
From Robert Israel, May 24 2019: (Start)
If p is an odd prime, then a((p+3)/2) = 4*p.
If p > 2 is in A067774, then a((p+5)/2) = 9*p. (End)
LINKS
Robert Israel, Table of n, a(n) for n = 3..10000
MAPLE
N:= 100: # for a(3)..a(N)
P:= select(isprime, [2, seq(i, i=3..2*N+1, 2)]): nP:= nops(P):
A:= Vector([infinity$(2*N+1)]):
for i from 1 to nP while 2*P[i] <= 2*N+1 do
p:= P[i];
for j from i to nP while p+P[j] <= 2*N+1 do
if p*P[j] < A[p+P[j]] then A[p+P[j]]:= p*P[j] fi
od od:
B:= Vector([infinity$(2*N+1)]):
for i from 1 to nP while 3*P[i] <= 2*N+1 do
p:= P[i];
for x from 4 to 2*N+1-p do
y:= p+x;
if A[x]*p < B[y] then B[y]:= A[x]*p fi
od od:
[seq(B[2*i+1], i=3..N)]; # Robert Israel, May 24 2019
CROSSREFS
KEYWORD
nonn,look
AUTHOR
Omar E. Pol, Jun 29 2012
STATUS
approved