This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A164843 #15 Feb 16 2025 08:33:11 %S A164843 177,120,233,432,733,1154,1731,2470,3417,4584,6013,7712,9731,12088, %T A164843 14807,17940,21501,25530,30021,35086,40675,46840,53631,61092,69251, %U A164843 78100,87697,98084,109309,121380,134377,148258,163043 %N A164843 The smallest magic constant of an n X n magic square with distinct prime entries. %C A164843 a(n) >= m(n), where m(n) is the smallest integer of the same parity as n, which is >= (Sum_{k=1..n^2} prime(k+1))/n. For example, Sum_{k=1..5^2} prime(k+1)/5=231.8, so m(5)=233. Conjecture: for n > 4, a(n)=m(n) or a(n)=m(n)+2. %H A164843 Harvey Heinz, <a href="http://www.magic-squares.net/primesqr.htm">Prime magic squares</a> %H A164843 A. Lelechenko and N. Makarova, <a href="/A164843/a164843.txt">Examples of prime magic n X n squares with minimal magic constant for n=5..13.</a> %H A164843 N. Makarova, <a href="http://www.natalimak1.narod.ru/sqmin1.htm">Smallest prime magic squares, Part I</a> (in Russian) %H A164843 N. Makarova, <a href="http://www.natalimak1.narod.ru/sqmin2.htm">Smallest prime magic squares, Part II</a> (in Russian) %H A164843 Mathworld, <a href="https://mathworld.wolfram.com/PrimeMagicSquare.html">Prime magic squares</a> %H A164843 PlanetMath, <a href="http://planetmath.org/encyclopedia/PrimeMagicSquare.html">Prime magic squares</a> %H A164843 Stefano Tognon, <a href="http://digilander.libero.it/ice00/magic/prime/PrimeAnalysis.html">Prime Analysis</a> %e A164843 From _Natalia Makarova_, Sep 26 2009: (Start) %e A164843 Here is a 14 X 14 example: %e A164843 [ 3 43 59 131 181 271 383 599 797 919 971 1039 1123 1193 %e A164843 1151 433 967 211 337 491 397 691 83 523 593 773 449 613 %e A164843 263 373 101 1063 877 617 419 911 787 241 151 839 739 331 %e A164843 503 439 809 1051 1091 659 157 1031 71 139 379 179 743 461 %e A164843 173 647 1069 389 1049 19 311 223 317 1103 283 947 499 683 %e A164843 547 13 1061 353 229 853 677 751 571 983 1201 29 193 251 %e A164843 643 269 887 733 23 409 1129 191 769 401 47 1109 149 953 %e A164843 163 881 673 107 431 487 991 631 829 109 349 367 811 883 %e A164843 1163 827 607 1171 443 653 463 5 457 577 31 293 601 421 %e A164843 509 1097 313 757 167 709 761 347 857 137 619 233 89 1117 %e A164843 1093 1019 7 521 1033 61 73 941 1009 859 701 11 127 257 %e A164843 53 467 97 307 1153 557 1021 569 359 937 821 113 977 281 %e A164843 907 17 823 641 661 929 67 719 79 587 479 563 1013 227 %e A164843 541 1187 239 277 37 997 863 103 727 197 1087 1217 199 41 ] %e A164843 (End) %e A164843 Comment from _N. J. A. Sloane_, Sep 28 2009: this contains 192 consecutive primes, 3 to 1171, plus 1187, 1193, 1201, 1217. %e A164843 For the 3 X 3 case see A024351. For the 4 X 4 magic square see the Mathworld link. %Y A164843 Cf. A073502, A073350, A125007. %K A164843 nonn,more %O A164843 3,1 %A A164843 _Andrew Lelechenko_, Aug 28 2009 and _Natalia Makarova_, Sep 08 2009 %E A164843 Partially reworded by _R. J. Mathar_, Aug 31 2009 %E A164843 Edited by _N. J. A. Sloane_, Sep 14 2009 %E A164843 a(11)-a(15) from _Natalia Makarova_, a(16)-a(35) from _Natalia Makarova_ and Stefano Tognon %E A164843 Edited by _Max Alekseyev_, Feb 11 2010