cp's OEIS Frontend

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.

A322261 Square array T(n, k) (n >= 0, k >= 0) read by antidiagonals upwards: the lengths of runs in binary expansion of T(n, k) correspond to the lengths of runs in binary expansion of n followed by the lengths of runs in binary expansion of k.

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%I A322261 #9 Dec 04 2018 15:26:48
%S A322261 0,1,1,2,2,2,3,5,5,3,4,6,10,4,4,5,9,13,11,11,5,6,10,18,12,20,10,6,7,
%T A322261 13,21,19,27,21,9,7,8,14,26,20,36,26,22,8,8,9,17,29,27,43,37,25,23,23,
%U A322261 9,10,18,34,28,52,42,38,24,40,22,10,11,21,37,35,59,53
%N A322261 Square array T(n, k) (n >= 0, k >= 0) read by antidiagonals upwards: the lengths of runs in binary expansion of T(n, k) correspond to the lengths of runs in binary expansion of n followed by the lengths of runs in binary expansion of k.
%C A322261 The array T is associative.
%H A322261 <a href="http://oeis.org/index/Bi#binary">Index entries for sequences related to binary expansion of n</a>
%F A322261 T(n, 0) = T(0, n) = n.
%F A322261 T(n, 1) = A042963(n+1).
%F A322261 T(n, 2) = A047617(n+1).
%F A322261 T(n, 3) = A047457(n+1).
%F A322261 T(1, n) = A010078(n+1).
%F A322261 T(2, n) = A004757(n) for any n > 0.
%F A322261 A005811(T(n, k)) = A005811(n) + A005811(k).
%F A322261 T(2*n, k) = A163621(2*n, k) for any n > 0 and k > 0.
%F A322261 T(2*n, 2*n) = A020330(2*n) for any n > 0.
%e A322261 Array T(n, k) begins (in decimal):
%e A322261   n\k|  0   1   2   3   4   5   6   7    8    9   10   11   12
%e A322261   ---+--------------------------------------------------------
%e A322261     0|  0   1   2   3   4   5   6   7    8    9   10   11   12
%e A322261     1|  1   2   5   4  11  10   9   8   23   22   21   20   19
%e A322261     2|  2   5  10  11  20  21  22  23   40   41   42   43   44
%e A322261     3|  3   6  13  12  27  26  25  24   55   54   53   52   51
%e A322261     4|  4   9  18  19  36  37  38  39   72   73   74   75   76
%e A322261     5|  5  10  21  20  43  42  41  40   87   86   85   84   83
%e A322261     6|  6  13  26  27  52  53  54  55  104  105  106  107  108
%e A322261     7|  7  14  29  28  59  58  57  56  119  118  117  116  115
%e A322261     8|  8  17  34  35  68  69  70  71  136  137  138  139  140
%e A322261 Array T(n, k) begins (in binary):
%e A322261   n\k |     0      1      10      11      100      101      110      111      1000
%e A322261   ----+---------------------------------------------------------------------------
%e A322261      0|     0      1      10      11      100      101      110      111      1000
%e A322261      1|     1     10     101     100     1011     1010     1001     1000     10111
%e A322261     10|    10    101    1010    1011    10100    10101    10110    10111    101000
%e A322261     11|    11    110    1101    1100    11011    11010    11001    11000    110111
%e A322261    100|   100   1001   10010   10011   100100   100101   100110   100111   1001000
%e A322261    101|   101   1010   10101   10100   101011   101010   101001   101000   1010111
%e A322261    110|   110   1101   11010   11011   110100   110101   110110   110111   1101000
%e A322261    111|   111   1110   11101   11100   111011   111010   111001   111000   1110111
%e A322261   1000|  1000  10001  100010  100011  1000100  1000101  1000110  1000111  10001000
%o A322261 (PARI) torl(n) = my (r=[]); while (n, r = concat(valuation(n+(n%2),2), r); n \= 2^r[1];); r
%o A322261 fromrl(r) = my (v=0); for (i=1, #r, v = (v + (i%2))*2^r[i]-(i%2)); v
%o A322261 T(n,k) = fromrl(concat(torl(n), torl(k)))
%Y A322261 Cf. A004757, A005811, A010078, A020330, A042963, A047457, A047617, A101211, A163621.
%K A322261 nonn,tabl,base
%O A322261 0,4
%A A322261 _Rémy Sigrist_, Dec 01 2018