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%I #10 Oct 20 2022 16:26:38
%S 1,1,2,2,4,8,11,19,31,50,88,146,241,407,675,1118,1871,3102,5175,8633,
%T 14394,23999,40002,66666,111044,185192,308442,514138,857283,1428537,
%U 2381021
%N Row lengths of the irregular triangles A324038 and A324246.
%F a(n) = 2*a(n-1) - a_1(n-1), for n >= 2, and a(0) = 1 = a(1), where a_1(k) is the number of entries 1 (mod 3) in row k of A324246 given in A324040(k).
%e a(5) = 8 = 2*a(4) because a_1(4) = A324040(4) = 0.
%e a(6) = 2*a(5) - 5 = 16 - 5 = 11 because a_1(5) = A324040(5) = 5.
%Y Cf. A324038, A324040, A324246.
%K nonn,easy
%O 0,3
%A _Nicolas Vaillant_, Philippe Delarue, _Wolfdieter Lang_, May 09 2019
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