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 A267502 #21 Mar 16 2018 05:21:14 %S A267502 0,3,0,0,0,3,9,18,45 %N A267502 Number of cycles of length 3 of autobiographical numbers (A267491 ... A267498) in base n. %C A267502 a(n) is the number of cycles of length 3 of autobiographical numbers in base n. For n>=5, it seems that a(n)=3/2*n^2-33/2*n+45 describes the number of cycles of length 3 in base n. The formula is correct for 5<=n<=11, but unknown for n>11. We assume it's correct for all n>=5. %D A267502 Antonia Münchenbach and Nicole Anton George, "Eine Abwandlung der Conway-Folge", contribution to "Jugend forscht" 2016, 2016 %F A267502 Conjecture: a(n) = 3/2*n^2 - 33/2*n + 45. The formula is correct for 5<=n<=11, but unknown for n>11. We assume it's correct for all n>=5. %e A267502 In base two, four, five and six there is no cycle of length 3. %e A267502 In base three, there is 1 cycle of length 3 with 3 numbers: 10011112, 10101102, 2012112. %e A267502 In base 10, there are 6 cycles of length 3 (18 numbers). %Y A267502 Cf. A047841, A267491, A267492, A267493, A267494, A267495, A267496, A267497, A267498, A267499, A267500, A267501, A267502. %K A267502 nonn,base,more %O A267502 2,2 %A A267502 _Antonia Münchenbach_, Jan 28 2016