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%I #25 Mar 02 2017 05:43:27
%S 1,7,7,49,7,49,49,343,7,49,49,343,49,343,343,2401,7,49,49,343,49,343,
%T 343,2401,49,343,343,2401,343,2401,2401,16807,7,49,49,343,49,343,343,
%U 2401,49,343,343,2401,343,2401,2401,16807,49,343,343,2401,343,2401,2401,16807,343,2401,2401,16807,2401,16807,16807,117649
%N a(n) = 7^A000120(n).
%C Also first differences of A161342.
%C From _Omar E. Pol_, May 03 2015: (Start)
%C It appears that when A151785 is regarded as a triangle in which the row lengths are the powers of 2, this is what the rows converge to.
%C Also this is also a row of the square array A256140.
%C (End)
%H N. J. A. Sloane, <a href="/wiki/Catalog_of_Toothpick_and_CA_Sequences_in_OEIS">Catalog of Toothpick and Cellular Automata Sequences in the OEIS</a>
%H <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%F a(n) = A000420(A000120(n)). - _Omar E. Pol_, May 03 2015
%F G.f.: Product_{k>=0} (1 + 7*x^(2^k)). - _Ilya Gutkovskiy_, Mar 02 2017
%e From _Omar E. Pol_, May 03 2015: (Start)
%e Also, written as an irregular triangle in which the row lengths are the terms of A011782, the sequence begins:
%e 1;
%e 7;
%e 7, 49;
%e 7, 49, 49, 343;
%e 7, 49, 49, 343, 49, 343, 343, 2401;
%e 7, 49, 49, 343, 49, 343, 343, 2401, 49, 343, 343, 2401, 343, 2401, 2401, 16807;
%e ...
%e Row sums give A055274.
%e Right border gives A000420.
%e (End)
%o (PARI) a(n) = 7^hammingweight(n); \\ _Omar E. Pol_, May 03 2015
%Y Cf. A000420, A011782, A055274, A160410, A151785, A161411, A160428, A160429, A161342, A256140, A256141.
%Y Rows of the array A256140 are: A000007, A000012, A001316, A048883, A102376, A256135, A256136, this sequence.
%K nonn
%O 0,2
%A _Omar E. Pol_, Jun 14 2009
%E More terms from _Sean A. Irvine_, Mar 08 2011
%E New name from _Omar E. Pol_, May 03 2015
%E a(52)-a(63) from _Omar E. Pol_, May 16 2015
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