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 A100462 #10 Apr 07 2023 09:26:42 %S A100462 1,1,1,3,7,25,49,109,229,481,1003,2019,4051,8143,16309,32683,65439, %T A100462 131007,262081,524187,1048423,2097027,4194147,8388481,16777039, %U A100462 33554269,67108699,134217529,268435227,536870713,1073741607,2147483371,4294967043,8589934267,17179868869 %N A100462 Leading diagonal of array in A100461. %H A100462 G. C. Greubel, <a href="/A100462/b100462.txt">Table of n, a(n) for n = 1..1000</a> %t A100462 t[n_, k_]:= t[n, k]= If[k==1, 2^(n-1), (n-k+1)*Floor[(t[n,k-1] -1)/(n - k+1)]]; (* t = A100461 *) %t A100462 Table[t[n,n], {n,40}] (* _G. C. Greubel_, Apr 07 2023 *) %o A100462 (Magma) %o A100462 function t(n,k) // t = A100461 %o A100462 if k eq 1 then return 2^(n-1); %o A100462 else return (n-k+1)*Floor((t(n,k-1) -1)/(n-k+1)); %o A100462 end if; %o A100462 end function; %o A100462 [t(n,n): n in [1..40]]; // _G. C. Greubel_, Apr 07 2023 %o A100462 (SageMath) %o A100462 def t(n,k): # t = A100461 %o A100462 if (k==1): return 2^(n-1) %o A100462 else: return (n-k+1)*((t(n, k-1) -1)//(n-k+1)) %o A100462 [t(n,n) for n in range(1,41)] # _G. C. Greubel_, Apr 07 2023 %Y A100462 Cf. A100461, A100463. %K A100462 nonn %O A100462 1,4 %A A100462 _N. J. A. Sloane_, Nov 22 2004