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 A048135 #18 Apr 02 2025 15:16:39
%S A048135 3,4,5,6,7,8,9,10,12,13,14,15,16,17,18,19,20,21,24,26,27,28,30,32,34,
%T A048135 35,36,37,38,39,40,42,45,48,51,52,54,56,57,60,63,64,65,68,70,72,73,74,
%U A048135 76,78,80,81,84,85,90,91,95,96,97,102,104,105,108,109,111,112
%N A048135 Tomahawk-constructible n-gons.
%H A048135 Andrew M. Gleason, <a href="http://www.jstor.org/stable/2323624">Angle Trisection, the Heptagon and the Triskaidecagon</a>, American Mathematical Monthly, 95 (1988), 185-194.
%F A048135 a(n) = A122254(n+2); A122255(a(n)) = 1. - _Reinhard Zumkeller_, Aug 29 2006
%o A048135 (Python)
%o A048135 from itertools import count, islice
%o A048135 from sympy import primefactors, totient
%o A048135 def A048135_gen(): # generator of terms
%o A048135 yield from filter(lambda n: set(primefactors(totient(n))) <= {2,3}, count(3))
%o A048135 A048135_list = list(islice(A048135_gen(),66)) # _Chai Wah Wu_, Apr 02 2025
%Y A048135 Cf. A005109, A048136, A122254, A122255.
%K A048135 nonn
%O A048135 1,1
%A A048135 _David W. Wilson_