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 A053227 #10 Oct 27 2023 22:00:45 %S A053227 1,4,2,6,14,13,19,10,12,29,2,26,40,15,6,53,4,48,52,6,6,24,67,21,44,48, %T A053227 40,30,106,43,76,30,72,121,44,88,65,42,116,12,90,122,40,24,154,15,115, %U A053227 112,18,30,54,170,64,134,96,28,2,36,227,18,68,184,79,120,176,132,148 %N A053227 First differences of sigma(n) that are negative. %H A053227 Harvey P. Dale, <a href="/A053227/b053227.txt">Table of n, a(n) for n = 1..1000</a> %F A053227 a(n) = A053222(A053226(n)) %p A053227 with(numtheory): seq( `if`((sigma(i) > sigma(i+1)),(sigma(i) - sigma(i+1)),print( )), i=1..200); %t A053227 Abs[Select[Differences[DivisorSigma[1,Range[200]]],#<0&]] (* _Harvey P. Dale_, Apr 17 2022 *) %Y A053227 Cf. A000203, A053222, A053225. %K A053227 nonn %O A053227 1,2 %A A053227 _Asher Auel_, Jan 06 2000