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 A114735 #16 May 10 2025 03:08:29 %S A114735 3,15,231,431985 %N A114735 Least odd number k such that Phi(k,x) is a flat cyclotomic polynomial of order n. %C A114735 A flat polynomial is defined to be a polynomial whose coefficients are -1, 0, or 1. Order n means that k is the product of n distinct odd primes. Although the first four numbers are triangular (A000217), this appears to be a coincidence. Are there flat cyclotomic polynomials of all orders? %C A114735 Conjecture that the next two terms are 746443728915 = 3 * 5 * 31 * 929 * 1727939 and 7800513423460801052132265 = 3 * 5 * 31 * 929 * 1727941 * 10450224300389. [_T. D. Noe_, Apr 13 2010] %C A114735 In 2010, Andrew Arnold reported to me that the order of 746443728915 is 3. His paper has details about how the computation was done. - _T. D. Noe_, Mar 20 2013 %H A114735 Andrew Arnold and Michael Monagan, <a href="http://dx.doi.org/10.1090/S0025-5718-2011-02467-1">Calculating cyclotomic polynomials</a>, Mathematics of Computation 80 (276) (2011) 2359-2379; <a href="https://wayback.cecm.sfu.ca/~ada26/cyclotomic/PDFs/CalcCycloPolysApr2010.pdf">preprint</a>. %Y A114735 Cf. A117223 (third-order flat cyclotomic polynomials), A117318 (fourth-order flat cyclotomic polynomials). %K A114735 nonn,more %O A114735 1,1 %A A114735 _T. D. Noe_, Mar 14 2006