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 A171710 #17 Feb 19 2019 15:42:34
%S A171710 3,3,5,5,13,13,13,13,13,13,13,13,21,21,21,21,21,21,21,21,39,39,39,39,
%T A171710 39,39,39,39,39,39,39,39,39,39,39,39,39,39,57,57,57,57,57,57,57,57,57,
%U A171710 57,57,57,57,57,57,57,57,57,89,89,89,89,89,89,89,89,89,89,89,89,89,89,89
%N A171710 Union of A168234 and A171219, sorted.
%C A171710 Consider a table T(n,k) similar to A168142 = {2,1}, {8,7,6,...,2,1}, {18,17,...,2,1},... that repeats each row. Thus T(n,k) = {2,1}, {2,1}, {8,7,6,...,2,1}, {8,7,6,...,2,1}, {18,17,...,2,1}, etc. The rows of T(n,k) decrement from 2*ceiling(n/2)^2 to 1. Then we can construct the table of atomic numbers in the Janet periodic table A138509(n) = T(n,k) + a(n), with k=2*ceiling(n/2)^2 - 1 down to 1 by step -1.
%H A171710 Michael De Vlieger, <a href="/A171710/b171710.txt">Table of n, a(n) for n = 1..10680</a> (first 39 rows)
%F A171710 May be regarded as an irregular triangle read by rows, defined by T(n,k) = A168380(n) + 1, with 1 <= k <= ceiling(n/2)^2. - _Michael De Vlieger_, Jul 20 2016
%t A171710 Table[(n + 1) (3 + 2 n^2 + 4 n - 3 (-1)^n)/12 + 1, {n, 7}, {k, 2 Ceiling[n/2]^2}] // Flatten (* _Michael De Vlieger_, Jul 20 2016 *)
%Y A171710 Cf. A138509 (Janet periodic table, rows n > 1 end in the repeated numbers in this sequence), A168234 (odd rows), A168380 (repeated numbers k - 1), A171219 (even rows), A172002 (smallest values of rows n > 1 are the repeated numbers in this sequence).
%K A171710 nonn,tabf
%O A171710 1,1
%A A171710 _Paul Curtz_, Dec 16 2009