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 A028318 #14 Jul 02 2025 16:01:56
%S A028318 1,5,6,7,12,8,19,9,27,38,10,36,65,11,46,101,130,57,147,231,13,69,204,
%T A028318 378,462,14,82,273,582,840,15,96,355,855,1422,1680,16,111,451,1210,
%U A028318 2277,3102,17,127,562,1661,3487,5379,6204,18,144,689,2223,5148,8866
%N A028318 Distinct elements in the 5-Pascal triangle A028313.
%H A028318 G. C. Greubel, <a href="/A028318/b028318.txt">Table of n, a(n) for n = 0..1000</a>
%t A028318 DeleteDuplicates[Table[If[n<2, 1, Binomial[n,k] +3*Binomial[n-2,k-1]], {n,0,30}, {k,0,n}]//Flatten] (* _G. C. Greubel_, Jul 03 2024 *)
%o A028318 (SageMath)
%o A028318 def A028323(n, k): return 1 if n<2 else binomial(n, k) + 3*binomial(n-2, k-1)
%o A028318 b=flatten([[A028323(n, k) for k in range(n+1)] for n in range(31)])
%o A028318 def a(seq): # order preserving
%o A028318 nd = [] # no duplicates
%o A028318 [nd.append(i) for i in seq if not nd.count(i)]
%o A028318 return nd
%o A028318 a(b) # A028318 # _G. C. Greubel_, Jul 03 2024
%K A028318 nonn
%O A028318 0,2
%A A028318 _Mohammad K. Azarian_
%E A028318 More terms from _James Sellers_, Dec 08 1999