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 A112874 #5 Feb 16 2025 08:32:59 %S A112874 3,4,5,6,7,10,11,12,26,160,3787,31877 %N A112874 Numbers n such that the coefficient of x^n in (x^2-x-1)^n is prime. %C A112874 n=31877 yields a probable prime; the others have been proved prime. These n were also found by Eric Weisstein, who found no other n<100000. %H A112874 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CentralTrinomialCoefficient.html">Central Trinomial Coefficient</a> %H A112874 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/IntegerSequencePrimes.html">Integer Sequence Primes</a> %t A112874 Select[Range[200], PrimeQ[Coefficient[Expand[(x^2-x-1)^# ], x, # ]]&] %Y A112874 Cf. A098331 (coefficient of x^n in (x^2-x-1)^n). %K A112874 hard,nonn %O A112874 1,1 %A A112874 _T. D. Noe_, Sep 29 2005