OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..5080
EXAMPLE
MAPLE
isc10:= proc(n) issqr(20*n+5) end proc:
P:= select(isprime, [seq(seq(10*i+j, j=[-1, 1]), i=1..1000)]): nP:= nops(P):
M:= P[1]*P[2]*P[-1]:
A:= NULL:
for i from 1 to nP-2 while P[i]^3 < M do
for j from i+1 to nP-1 while P[i]*P[j]^2 < M do
for k from j+1 to nP do
q:= P[i]*P[j]*P[k];
if q > M then break fi;
if isc10(q) then A:= A, q fi
od od od:
sort([A]); # Robert Israel, Dec 24 2023
MATHEMATICA
Select[Table[5*n*(n+1) + 1, {n, 1, 330}], FactorInteger[#][[;; , 2]] == {1, 1, 1} &] (* Amiram Eldar, Dec 24 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Massimo Kofler, Dec 24 2023
STATUS
approved