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A271709 Table T(n,k) = 2^n + 2^k read by antidiagonals.

%I A271709 #26 Apr 15 2016 13:46:13
%S A271709 2,3,3,5,4,5,9,6,6,9,17,10,8,10,17,33,18,12,12,18,33,65,34,20,16,20,
%T A271709 34,65,129,66,36,24,24,36,66,129,257,130,68,40,32,40,68,130,257,513,
%U A271709 258,132,72,48,48,72,132,258,513,1025,514,260,136,80,64,80,136
%N A271709 Table T(n,k) = 2^n + 2^k read by antidiagonals.
%C A271709 n > 1 is in this sequence if and only if it is in A018900 or A000079.
%H A271709 Peter Kagey, <a href="/A271709/b271709.txt">Table of n, a(n) for n = 0..10000</a>
%F A271709 T(n,k) = T(k,n) = A173786(n,k). - _R. J. Mathar_, Apr 15 2016
%e A271709 a(0) = T(0, 0) = 2^0 + 2^0 = 2
%e A271709 a(1) = T(1, 0) = 2^1 + 2^0 = 3
%e A271709    2,   3,   5,   9,  17,  33,  65, 129, 257, 513,1025,
%e A271709    3,   4,   6,  10,  18,  34,  66, 130, 258, 514,1026,
%e A271709    5,   6,   8,  12,  20,  36,  68, 132, 260, 516,1028,
%e A271709    9,  10,  12,  16,  24,  40,  72, 136, 264, 520,1032,
%e A271709   17,  18,  20,  24,  32,  48,  80, 144, 272, 528,1040,
%e A271709   33,  34,  36,  40,  48,  64,  96, 160, 288, 544,1056,
%e A271709   65,  66,  68,  72,  80,  96, 128, 192, 320, 576,1088,
%e A271709  129, 130, 132, 136, 144, 160, 192, 256, 384, 640,1152,
%e A271709  257, 258, 260, 264, 272, 288, 320, 384, 512, 768,1280,
%e A271709  513, 514, 516, 520, 528, 544, 576, 640, 768,1024,1536,
%e A271709 1025,1026,1028,1032,1040,1056,1088,1152,1280,1536,2048,
%p A271709 A271709 := proc(n,k)
%p A271709     2^n+2^k ;
%p A271709 end proc: # _R. J. Mathar_, Apr 15 2016
%t A271709 Table[2^(n - k) + 2^k, {n, 0, 10}, {k, 0, n}] // Flatten (* _Michael De Vlieger_, Apr 12 2016 *)
%o A271709 (PARI) T(n, k) = 2^n + 2^k;
%o A271709 matrix(10, 10, n, k, n--;k--;T(n,k)) \\ _Michel Marcus_, Apr 12 2016
%Y A271709 Cf. A173786, A271710.
%K A271709 nonn,tabl,easy
%O A271709 0,1
%A A271709 _Peter Kagey_, Apr 12 2016