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 A173787 #16 Sep 08 2022 08:45:50 %S A173787 0,1,0,3,2,0,7,6,4,0,15,14,12,8,0,31,30,28,24,16,0,63,62,60,56,48,32, %T A173787 0,127,126,124,120,112,96,64,0,255,254,252,248,240,224,192,128,0,511, %U A173787 510,508,504,496,480,448,384,256,0,1023,1022,1020,1016,1008,992,960,896,768,512,0 %N A173787 Triangle read by rows: T(n,k) = 2^n - 2^k, 0 <= k <= n. %H A173787 G. C. Greubel, <a href="/A173787/b173787.txt">Rows n = 0..50 of the triangle, flattened</a> %F A173787 A000120(T(n,k)) = A025581(n,k). %F A173787 Row sums give A000337. %F A173787 Central terms give A020522. %F A173787 T(2*n+1, n) = A006516(n+1). %F A173787 T(2*n+3, n+2) = A059153(n). %F A173787 T(n, k) = A140513(n,k) - A173786(n,k), 0 <= k <= n. %F A173787 T(n, k) = A173786(n,k) - A059268(n+1,k+1), 0 < k <= n. %F A173787 T(2*n, 2*k) = T(n,k) * A173786(n,k), 0 <= k <= n. %F A173787 T(n, 0) = A000225(n). %F A173787 T(n, 1) = A000918(n) for n>0. %F A173787 T(n, 2) = A028399(n) for n>1. %F A173787 T(n, 3) = A159741(n-3) for n>3. %F A173787 T(n, 4) = A175164(n-4) for n>4. %F A173787 T(n, 5) = A175165(n-5) for n>5. %F A173787 T(n, 6) = A175166(n-6) for n>6. %F A173787 T(n, n-4) = A110286(n-4) for n>3. %F A173787 T(n, n-3) = A005009(n-3) for n>2. %F A173787 T(n, n-2) = A007283(n-2) for n>1. %F A173787 T(n, n-1) = A000079(n-1) for n>0. %F A173787 T(n, n) = A000004(n). %e A173787 Triangle begins as: %e A173787 0; %e A173787 1, 0; %e A173787 3, 2, 0; %e A173787 7, 6, 4, 0; %e A173787 15, 14, 12, 8, 0; %e A173787 31, 30, 28, 24, 16, 0; %t A173787 Table[2^n -2^k, {n,0,15}, {k,0,n}]//Flatten (* _G. C. Greubel_, Jul 13 2021 *) %o A173787 (Magma) [2^n -2^k: k in [0..n], n in [0..15]]; // _G. C. Greubel_, Jul 13 2021 %o A173787 (Sage) flatten([[2^n -2^k for k in (0..n)] for n in (0..15)]) # _G. C. Greubel_, Jul 13 2021 %K A173787 nonn,easy,tabl %O A173787 0,4 %A A173787 _Reinhard Zumkeller_, Feb 28 2010