OFFSET
0,2
COMMENTS
a(42) = 525 seems to be the largest odd term.
Note that switching p and q does not make a different triple. - Robert Israel, Mar 09 2018
LINKS
Robert Israel, Table of n, a(n) for n = 0..6567 (n=0..500 from Reinhard Zumkeller)
EXAMPLE
A100951(37) = #{2*3+31,2*7+23,2*13+11,2*17+3,5*7+2} = 5.
MAPLE
N:= 10^4: # to get terms before the first term > N
Primes:= select(isprime, [2, seq(i, i=3..N, 2)]):
V:= Vector(N):
for r in Primes do
for j from 1 while Primes[j]^2 <= N do
p:= Primes[j];
if p = r then next fi;
for k from j+1 while p*Primes[k]+r <= N do
q:= Primes[k];
if q = r then next fi;
V[p*q+r]:= V[p*q+r]+1;
od
od
od:
mv:= max( V):
F:= Vector(mv):
for i from 1 to N do
if V[i] > 0 and F[V[i]] = 0 then F[V[i]]:= i fi
od:
F0:= min(select(t -> F[t] = 0, [$1..max(V)])):
1, seq(F[i], i=1..F0-1); # Robert Israel, Mar 09 2018
N:= 10^4: # to get terms before the first term > N
Primes:= select(isprime, [2, seq(i, i=3..N, 2)]):
V:= Vector(N):
for r in Primes do
for j from 1 while Primes[j]^2 <= N do
p:= Primes[j];
if p = r then next fi;
for k from j+1 to nops(Primes) while p*Primes[k]+r <= N do
q:= Primes[k];
if q = r then next fi;
V[p*q+r]:= V[p*q+r]+1;
od
od
od:
mv:= max( V):
F:= Vector(mv):
for i from 1 to N do
if V[i] > 0 and F[V[i]] = 0 then F[V[i]]:= i fi
od:
F0:= min(select(t -> F[t] = 0, [$1..max(V)])):
if F0 = infinity then F0:= mv fi:
1, seq(F[i], i=1..F0-1); # Robert Israel, Mar 09 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, May 11 2009
STATUS
approved