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 A158483 #15 May 08 2022 22:49:15 %S A158483 0,1,3,9,1,28,7,90,35,1,297,154,11,1001,637,77,1,3432,2548,440,15, %T A158483 11934,9996,2244,135,1,41990,38760,10659,950,19,149226,149226,48279, %U A158483 5775,209,1,534888,572033,211508,31878,1748,23,1931540,2187185,904475,164450 %N A158483 Triangle read by rows: T(n,k) = (4k+3)/(n+2k+2)*binomial(2n,n+2k+1). %C A158483 This triangle forms a companion to A119245. %C A158483 Combinatorial interpretations of T(n,k): %C A158483 1) The number of standard tableaux of shape (n-2*k-1,n+2*k+1). %C A158483 2) The entries in column k are (with an offset of 2*k+1) the number of n-th generation vertices in the tree of sequences with unit increase labeled by 4*k+2. See [Sunik, Theorem 4]. %H A158483 Zoran Sunic, <a href="https://doi.org/10.37236/1745">Self describing sequences and the Catalan family tree</a>, Elect. J. Combin., 10 (No. 1, 2003). %F A158483 T(n,k) = (4*k+3)/(n+2*k+2)*binomial(2*n,n+2*k+1). %F A158483 O.g.f. y*C(y)^3/(1 - x*y^2*C(y)^4) = y + 3*y^2 + (9 + x)*y^3 + (28 + 7*x)*y^4 + ..., where C(x) = [1-(1-4*x)^(1/2)]/(2*x) is the o.g.f. for the Catalan numbers A000108. %F A158483 Row sums A001700. %e A158483 Triangle begins %e A158483 ================================== %e A158483 n\k|.....0.....1.....2.....3.....4 %e A158483 ================================== %e A158483 .0.|.....0 %e A158483 .1.|.....1 %e A158483 .2.|.....3 %e A158483 .3.|.....9.....1 %e A158483 .4.|....28.....7 %e A158483 .5.|....90....35.....1 %e A158483 .6.|...297...154....11 %e A158483 .7.|..1001...637....77.....1 %e A158483 .8.|..3432..2548...440....15 %e A158483 .9.|.11934..9996..2244...135.....1 %p A158483 with(combinat): T:=(n,k) -> (4k+3)/(n+2k+2)*binomial(2n,n+2k+1): for n from 0 to 13 do seq(T(n,k),k = 0..6); end do; %Y A158483 Cf. A000245 (column 0), A000588 (column 1), A000589 (column 2), A001700 (row sums), A119245. %K A158483 easy,nonn,tabf %O A158483 0,3 %A A158483 _Peter Bala_, Mar 20 2009