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 A363637 #4 Jul 15 2023 06:36:29 %S A363637 5,11,19,26,29,31,41,55,65,71,89,99,109,127,131,134,151,155,161,181, %T A363637 191,209,239,244,251,265,271,274,287,289,305,323,341,349,351,379,419, %U A363637 449,461,485,491,505,511,551,575,599,647,649,701,703,755,769,811,846,869 %N A363637 Indices of numbers of the form k^2-1, k >= 2, that can be written as a product of smaller numbers of that same form. %e A363637 5 is a term because 5^2-1 = 24 = 3*8 = (2^2-1)*(3^2-1) %e A363637 26 is a term because 26^2-1 = 675 = 3*15*15 = (2^2-1)*(4^2-1)^2. (This is the first term that requires more than two factors.) %Y A363637 Cf. A005563, A363636. %K A363637 nonn %O A363637 1,1 %A A363637 _Pontus von Brömssen_, Jun 19 2023