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 A164984 #13 Jul 22 2025 07:19:13 %S A164984 1,1,1,3,3,1,5,9,5,1,11,23,19,7,1,21,57,61,33,9,1,43,135,179,127,51, %T A164984 11,1,85,313,493,433,229,73,13,1,171,711,1299,1359,891,375,99,15,1, %U A164984 341,1593,3309,4017,3141,1641,573,129,17,1 %N A164984 Odd (Jacobsthal) triangle. %C A164984 Alternate diagonal sums give A008619. %C A164984 Diagonals sums give A097076. - _Philippe Deléham_, Oct 13 2013 %F A164984 Excel formula: C6=2*C4+C5+B5+B4 with C5=a(1)=1 and C6=a(2) %F A164984 T(n,k) = T(n-1,k) + T(n-1,k-1) + 2*T(n-2,k) + T(n-2,k-1). - _Philippe Deléham_, Oct 13 2013 %e A164984 1 %e A164984 1,1 %e A164984 3,3,1 %e A164984 5,9,5,1 %e A164984 11,23,19,7,1 %e A164984 21,57,61,33,9,1 %e A164984 Pascal-like triangle based on a right-triangular sum (with the top multiplied by 2): For n=13 a(13)=2*a(3)+a(5)+a(8)+a(9)= 2+3+9+5=19. %Y A164984 Cf. A164981, A001045, A005408, A015518 (row sums), A008619 %Y A164984 Cf. A008288, A007318. %K A164984 nonn,tabl %O A164984 1,4 %A A164984 _Mark Dols_, Sep 03 2009, Sep 06 2009