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 A321160 #17 Dec 19 2024 11:48:12 %S A321160 220780,519156,1079001,1154440,1324576,1447551,2429505,2454705, %T A321160 2491776,2603601,2665125,2700621,2772225,2953665,3000025,3086721, %U A321160 3316600,3665376,4488561,4741660,5142501,5388201,5785101,6076225 %N A321160 Numbers that have exactly 10 representations as a k-gonal number, P(n,k) = n*((k-2)*n - (k-4))/2, k and n >= 3. %H A321160 Hugh Erling, <a href="/A321160/a321160.txt">Python program</a> %e A321160 a(1) 220780 has representations P(n,k) = P(4, 36798) = P(7, 10515) = P(10, 4908) = P(14, 2428) = P(19, 1293) = P(28, 586) = P(35, 373) = P(38, 316) = P(40, 285) = P(664, 3). %e A321160 a(2) 519156 has representations P(n,k) = P(3, 173053) = P(6, 34612) = P(8, 18543) = P(11, 9441) = P(27, 1481) = P(36, 826) = P(66, 244) = P(92, 126) = P(99, 109) = P(456, 7). %e A321160 a(3) 1079001 has representations P(n,k) = P(3, 359668) = P(6, 71935) = P(9, 29974) = P(11, 19620) = P(14, 11859) = P(21, 5140) = P(27, 3076) = P(66, 505) = P(81, 335) = P(126, 139). %o A321160 (Python) # See links. %o A321160 (PARI) isok(n) = sum(k=3, n-1, ispolygonal(n, k)) == 10; \\ _Michel Marcus_, Nov 02 2018 %Y A321160 Cf. A275256, A057145, A063778, A129654, A139601, A177029, A195527, A195528, A321156, A321157, A321158, A321159, A320943. %K A321160 nonn %O A321160 1,1 %A A321160 _Hugh Erling_, Oct 29 2018