

A170842


G.f.: Product_{k>=1} (1 + 2x^(2^k1) + 3x^(2^k)).


2



1, 2, 3, 2, 7, 12, 9, 2, 7, 12, 13, 20, 45, 54, 27, 2, 7, 12, 13, 20, 45, 54, 31, 20, 45, 62, 79, 150, 243, 216, 81, 2, 7, 12, 13, 20, 45, 54, 31, 20, 45, 62, 79, 150, 243, 216, 85, 20, 45, 62, 79, 150, 243, 224, 133, 150, 259, 344, 537, 936, 1161, 810, 243, 2, 7, 12, 13, 20, 45
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OFFSET

0,2


COMMENTS

It appears that this is also an irregular triangle read by rows (see the example).
It appears that right border gives A000244.
It appears that row sums give A052934. (End)


LINKS



EXAMPLE

Written as an irregular triangle in which row lengths are A000079 the sequence begins:
1;
2, 3;
2, 7, 12, 9;
2, 7, 12, 13, 20, 45, 54, 27;
2, 7, 12, 13, 20, 45, 54, 31, 20, 45, 62, 79, 150, 243, 216, 81;
2, 7, 12, 13, 20, 45, 54, 31, 20, 45, 62, 79, 150, 243, 216, 85, 20, 45, 62, ...
(End)


MATHEMATICA

CoefficientList[Series[Product[1+2x^(2^k1)+3x^2^k, {k, 10}], {x, 0, 70}], x] (* Harvey P. Dale, Apr 09 2021 *)


PROG

(PARI)
D_x(N) = {my( x='x+O('x^N)); Vec(prod(k=1, logint(N, 2)+1, (1+2*x^(2^k1)+3*x^(2^k))))}


CROSSREFS



KEYWORD

nonn,tabf


AUTHOR



STATUS

approved



