cp's OEIS Frontend

A129125 Prune the tree structure defined in sequence A129129 yielding a new irregular table with shape sequence A027336.

%I A129125 #10 Jul 24 2024 03:05:33
%S A129125 1,2,3,5,6,7,10,9,11,14,15,18,13,22,21,25,30,27,17,26,33,35,42,50,45,
%T A129125 54,19,34,39,55,66,49,70,63,75,90,81
%N A129125 Prune the tree structure defined in sequence A129129 yielding a new irregular table with shape sequence A027336.
%C A129125 A000041 begins 1 1 2 3 5 7 11 15 22 30 42 ... and when shifted 0 0 1 1 2 3 5 7 11 15 22 ... by subtraction yielding 1 1 1 2 3 4 6 8 11 15 20 ... shape seq A027336.
%e A129125 The original tree begins
%e A129125    1;
%e A129125    2;
%e A129125    3,  4;
%e A129125    5,  6,  8;
%e A129125    7, 10,  9, 12, 16;
%e A129125   11, 14, 15, 20, 18, 24, 32;
%e A129125   ...
%e A129125 Multiplying by four yields
%e A129125    4;
%e A129125    8;
%e A129125   12, 16;
%e A129125   20, 24, 32;
%e A129125   ...
%e A129125 These are the values to be omitted, leaving
%e A129125    1;
%e A129125    2;
%e A129125    3;
%e A129125    5,  6;
%e A129125    7, 10,  9;
%e A129125   11, 14, 15, 18;
%e A129125   ...
%Y A129125 Cf. A000041, A027336, A129129.
%K A129125 more,nonn,tabf
%O A129125 0,2
%A A129125 _Alford Arnold_, Apr 04 2007