A375459 - OEIS

%I #11 Sep 13 2024 07:34:04

%S 21,18,15,51,195,435,76035

%N a(n) = smallest magic sum of any 3 X 3 magic square which contains exactly n squared primes, or 0 if no such magic square exists.

%C a(9) = 0.

%C a(n) = A268855(n+1) for n = 0, 1, 2, and 5.

%C a(7) and a(8) - if nonzero, they are greater than 10^10.

%H Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_079.htm">Puzzle 79. The Chebrakov's - by two months - challenge</a>, The Prime Puzzles and Problems Connection.

%H Arkadiusz Wesolowski, <a href="/A375459/a375459.txt">Examples of these magic squares</a>

%H <a href="/index/Mag#magic">Index entries for sequences related to magic squares</a>

%Y Cf. A001248, A268855, A375361.

%K nonn,fini,hard,more

%O 0,1

%A _Arkadiusz Wesolowski_, Aug 15 2024