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 A261173 #18 Apr 05 2020 22:26:53
%S A261173 11,0,101,0,0,0,0,10111,0,0,0,101111,0,0,0,0,0,0,1011001,0,0,0,
%T A261173 11110111,0,10011101,10010101,0,0,0,101111111,101101111,0,100100111,
%U A261173 101001001,0,0,0,0,1010111111,1001110111,0,1000011011,1000001011,0,0
%N A261173 Table read by antidiagonals: T(n,k) = smallest prime p containing only digits 0 and 1 with n 0's and k 1's, or 0 if no such p exists.
%C A261173 T(n, k) = 0 if k is a term of A008585.
%C A261173 T(0, k) != 0 iff k is a term of A004023.
%C A261173 T(1, k) = A157709(k-2) for all k >= 4.
%C A261173 T(n, 2) != 0 iff A062397(n+1) is prime.
%C A261173 a(n) is in A168586 iff it is the smallest p in T with A007953(p) = k.
%H A261173 Alois P. Heinz, <a href="/A261173/b261173.txt">Antidiagonals n = 0..20, flattened</a>
%e A261173 Table T(n, k) starts
%e A261173 k = 2 3 4 5
%e A261173 -------------------------------------
%e A261173 n = 0 | 11 0 0 0
%e A261173 n = 1 | 101 0 10111 101111
%e A261173 n = 2 | 0 0 0 0
%e A261173 n = 3 | 0 0 1011001 10011101
%o A261173 (PARI) a(n, k) = i=0; forprime(p=10^(n+k-1), (10^(n+k)-1)/9, if(vecmax(digits(p))==1 && sumdigits(p)==k, return(p); i++; break)); if(i==0, return(0))
%o A261173 table(row, col) = for(x=0, row, for(y=2, col, print1(a(x, y), " ")); print(""))
%o A261173 table(4, 5) \\ print 5 X 4 table
%Y A261173 Cf. A020449, A036929.
%K A261173 nonn,tabl,base
%O A261173 0,1
%A A261173 _Felix Fröhlich_, Aug 10 2015
%E A261173 More terms from _Alois P. Heinz_, Aug 17 2015