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 A047272 #31 Jul 02 2025 16:01:57 %S A047272 61,89,109,149,269,389,401,421,521,661,701,761,769,809,821,829,1009, %T A047272 1049,1069,1181,1249,1289,1301,1361,1381,1409,1429,1601,1721,1901, %U A047272 1949,2081,2089,2141,2221,2269,2309,2341,2381,2441,2549,2729,2741,2749,2789 %N A047272 Primes p such that p == 1 (mod 4) and Fibonacci((p-1)/4) is divisible by p. %C A047272 There are typos in Theorems 1 and 2 of Lehmer's paper. The condition a == 1 (mod 4) should be a == 1 (mod 2). - _Eric Rowland_, May 20 2018 %H A047272 E. Lehmer, <a href="https://web.archive.org/web/2024*/https://www.fq.math.ca/Scanned/4-2/lehmer.pdf">On the quadratic character of the Fibonacci root</a>, Fib. Quart., 4 (1966), 135-138. %H A047272 E. Lehmer, <a href="/A001583/a001583.pdf">On the quadratic character of the Fibonacci root</a> (annotated scanned copy) %t A047272 Select[Prime[Range[400]], Function[p, Mod[p, 4] == 1 && Divisible[Fibonacci[(p - 1)/4], p]]] (* _Eric Rowland_, May 20 2018 *) %Y A047272 For nonprimes see A091982. %K A047272 nonn,easy %O A047272 1,1 %A A047272 _N. J. A. Sloane_ %E A047272 More terms from _James Sellers_, Jan 25 2000 %E A047272 New Name from _Eric Rowland_, May 20 2018