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 A075773 #7 Mar 06 2025 23:21:12
%S A075773 3,4,4,7,9,9,5,5,13,15,17,19,21,21,4,16,25,27,27,20,18,18,33,35,35,19,
%T A075773 39,41,43,43,28,47,49,51,53,55,57,59,61,61,39,65,67,69,71,71,38,75,77,
%U A075773 79,81,81,47,85,87,89,89,68,71,71,12,95,97,99,101,103,103
%N A075773 Let {b(n)} be the sequence of perfect powers (A001597); then a(n) = max { b(n)-b(n-1), b(n+1)-b(n) }.
%e A075773 The perfect powers are 1, 4, 8, 9, 16, 25, 27, 32, 36, 49, 64, 81, 100, 121, etc. The 7th is 27. This is 2 larger than the 6th (25) and 5 smaller than the 8th (32). So a(7)=5.
%Y A075773 Cf. A001597, A053289, A075772.
%K A075773 nonn
%O A075773 1,1
%A A075773 _Neil Fernandez_, Oct 09 2002
%E A075773 Missing 4 inserted and more terms from _Sean A. Irvine_, Mar 06 2025