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 A143685 #10 Sep 08 2022 08:45:37
%S A143685 1,1,1,1,11,1,1,21,21,1,1,31,141,31,1,1,41,361,361,41,1,1,51,681,1991,
%T A143685 681,51,1,1,61,1101,5921,5921,1101,61,1,1,71,1621,13151,29761,13151,
%U A143685 1621,71,1,1,81,2241,24681,96201,96201,24681,2241,81,1,1,91,2961,41511,239241,460251,239241,41511,2961,91,1
%N A143685 Pascal-(1,9,1) array.
%H A143685 G. C. Greubel, <a href="/A143685/b143685.txt">Antidiagonal rows n = 0..50, flattened</a>
%F A143685 Square array: T(n, k) = T(n, k-1) + 9*T(n-1, k-1) + T(n-1, k) with T(n, 0) = T(0, k) = 1.
%F A143685 Number triangle: T(n,k) = Sum_{j=0..n-k} binomial(n-k,j)*binomial(k,j)*10^j.
%F A143685 Riordan array (1/(1-x), x*(1+9*x)/(1-x)).
%F A143685 T(n, k) = Hypergeometric2F1([-k, k-n], [1], 10). - _Jean-François Alcover_, May 24 2013
%F A143685 Sum_{k=0..n} T(n, k) = A002534(n+1). - _G. C. Greubel_, May 29 2021
%e A143685 Square array begins as:
%e A143685 1, 1, 1, 1, 1, 1, 1, ... A000012;
%e A143685 1, 11, 21, 31, 41, 51, 61, ... A017281;
%e A143685 1, 21, 141, 361, 681, 1101, 1621, ...
%e A143685 1, 31, 361, 1991, 5921, 13151, 24681, ...
%e A143685 1, 41, 681, 5921, 29761, 96201, 239241, ...
%e A143685 1, 51, 1101, 13151, 96201, 460251, 1565301, ...
%e A143685 1, 61, 1621, 24681, 239241, 1565301, 7272861, ...
%e A143685 Antidiagonal triangle begins as:
%e A143685 1;
%e A143685 1, 1;
%e A143685 1, 11, 1;
%e A143685 1, 21, 21, 1;
%e A143685 1, 31, 141, 31, 1;
%e A143685 1, 41, 361, 361, 41, 1;
%e A143685 1, 51, 681, 1991, 681, 51, 1;
%e A143685 1, 61, 1101, 5921, 5921, 1101, 61, 1;
%e A143685 1, 71, 1621, 13151, 29761, 13151, 1621, 71, 1;
%t A143685 Table[Hypergeometric2F1[-k, k-n, 1, 10], {n,0,12}, {k,0,n}]//Flatten (* _Jean-François Alcover_, May 24 2013 *)
%o A143685 (Magma)
%o A143685 A143685:= func< n,k,q | (&+[Binomial(k, j)*Binomial(n-j, k)*q^j: j in [0..n-k]]) >;
%o A143685 [A143685(n,k,9): k in [0..n], n in [0..12]]; // _G. C. Greubel_, May 29 2021
%o A143685 (Sage) flatten([[hypergeometric([-k, k-n], [1], 10).simplify() for k in (0..n)] for n in (0..12)]) # _G. C. Greubel_, May 29 2021
%Y A143685 Cf. A002534, A143680, A143682.
%Y A143685 Pascal (1,m,1) array: A123562 (m = -3), A098593 (m = -2), A000012 (m = -1), A007318 (m = 0), A008288 (m = 1), A081577 (m = 2), A081578 (m = 3), A081579 (m = 4), A081580 (m = 5), A081581 (m = 6), A081582 (m = 7), A143683 (m = 8), this sequence (m = 9).
%K A143685 easy,nonn,tabl
%O A143685 0,5
%A A143685 _Paul Barry_, Aug 28 2008