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 A239932 #29 Dec 07 2016 11:07:59 %S A239932 3,12,9,9,12,12,39,18,18,21,21,72,27,27,30,30,96,36,36,39,15,39,120, %T A239932 45,45,48,48,144,54,36,54,57,57,84,84,63,63,66,66,234,72,72,75,21,75, %U A239932 108,108,81,81,84,48,84,120,120,90,90,93,93,312 %N A239932 Triangle read by rows in which row n lists the parts of the symmetric representation of sigma(4n-2). %C A239932 Row n is a palindromic composition of sigma(4n-2). %C A239932 Row n is also the row 4n-2 of A237270. %C A239932 Row n has length A237271(4n-2). %C A239932 Row sums give A239052. %C A239932 Also row n lists the parts of the symmetric representation of sigma in the n-th arm of the second quadrant of the spiral described in A239660, see example. %C A239932 For the parts of the symmetric representation of sigma(4n-3), see A239931. %C A239932 For the parts of the symmetric representation of sigma(4n-1), see A239933. %C A239932 For the parts of the symmetric representation of sigma(4n), see A239934. %C A239932 We can find the spiral (mentioned above) on the terraces of the pyramid described in A244050. - _Omar E. Pol_, Dec 06 2016 %e A239932 The irregular triangle begins: %e A239932 3; %e A239932 12; %e A239932 9, 9; %e A239932 12, 12; %e A239932 39; %e A239932 18, 18; %e A239932 21, 21; %e A239932 72; %e A239932 27, 27; %e A239932 30, 30; %e A239932 96; %e A239932 36, 36; %e A239932 39, 15, 39; %e A239932 120; %e A239932 45, 45; %e A239932 48, 48; %e A239932 ... %e A239932 Illustration of initial terms in the second quadrant of the spiral described in A239660: %e A239932 . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ %e A239932 . | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _| %e A239932 . | | %e A239932 . | | %e A239932 . | | _ _ _ _ _ _ _ _ _ _ _ _ _ _ %e A239932 . _ _ _| | | _ _ _ _ _ _ _ _ _ _ _ _ _| %e A239932 . | | | | %e A239932 . _ _| _ _ _| | | %e A239932 . 72 _| | | | _ _ _ _ _ _ _ _ _ _ _ _ %e A239932 . _| _| 21 _ _| | | _ _ _ _ _ _ _ _ _ _ _| %e A239932 . | _| |_ _ _| | | %e A239932 . _ _| _| _ _| | | %e A239932 . | _ _| _| 18 _ _| | _ _ _ _ _ _ _ _ _ _ %e A239932 . | | | |_ _ _| | _ _ _ _ _ _ _ _ _| %e A239932 . _ _ _ _ _| | 21 _ _| _| | | %e A239932 . | _ _ _ _ _ _| | | _| _ _| | %e A239932 . | | _ _ _ _ _| | 18 _ _| | | _ _ _ _ _ _ _ _ %e A239932 . | | | _ _ _ _ _| | | 39 _| _ _| | _ _ _ _ _ _ _| %e A239932 . | | | | _ _ _ _| | _ _| _| | | %e A239932 . | | | | | _ _ _ _| | _| 12 _| | %e A239932 . | | | | | | _ _ _| | |_ _| _ _ _ _ _ _ %e A239932 . | | | | | | | _ _ _ _| 12 _ _| | _ _ _ _ _| %e A239932 . | | | | | | | | _ _ _| | 9 _| | %e A239932 . | | | | | | | | | _ _ _| 9 _|_ _| %e A239932 . | | | | | | | | | | _ _| | _ _ _ _ %e A239932 . | | | | | | | | | | | _ _| 12 _| _ _ _| %e A239932 . | | | | | | | | | | | | _| | %e A239932 . | | | | | | | | | | | | | _ _| %e A239932 . | | | | | | | | | | | | | | 3 _ _ %e A239932 . | | | | | | | | | | | | | | | _| %e A239932 . |_| |_| |_| |_| |_| |_| |_| |_| %e A239932 . %e A239932 For n = 7 we have that 4*7-2 = 26 and the 26th row of A237593 is [14, 5, 2, 2, 2, 1, 1, 2, 2, 2, 5, 14] and the 25th row of A237593 is [13, 5, 3, 1, 2, 1, 1, 2, 1, 3, 5, 13] therefore between both Dyck paths there are two regions (or parts) of sizes [21, 21], so row 7 is [21, 21]. %e A239932 The sum of divisors of 26 is 1 + 2 + 13 + 26 = A000203(26) = 42. On the other hand the sum of the parts of the symmetric representation of sigma(26) is 21 + 21 = 42, equaling the sum of divisors of 26. %Y A239932 Cf. A000203, A196020, A236104, A235791, A237270, A237271, A237591, A237593, A239052, A239660, A239931, A239933, A239934, A244050, A245092, A262626. %K A239932 nonn,tabf,more %O A239932 1,1 %A A239932 _Omar E. Pol_, Mar 29 2014