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Variant of A253028 using only even numbers: a mirror symmetric array of even numbers where the n-th term is equal to the number of terms in the n-th row of the array.
3

%I #8 Jun 22 2022 21:04:11

%S 2,4,6,2,4,8,10,6,2,4,8,12,14,16,18,10,12,20,22,14,6,2,4,8,16,24,26,

%T 18,10,6,2,4,8,12,20,28,30,22,14,16,24,32,34,36,38,26,28,40,42,30,18,

%U 10,12,20,32,44,46,34,22,14,6,2,4,8,16,24,36,48,50,38,26

%N Variant of A253028 using only even numbers: a mirror symmetric array of even numbers where the n-th term is equal to the number of terms in the n-th row of the array.

%C See the examples in A253028 for a detailed illustration of how the array is constructed.

%H Rémy Sigrist, <a href="/A354577/a354577.gp.txt">PARI program</a>

%e 1.........................2,4

%e 2.......................6,2,4,8

%e 3....................10,6,2,4,8,12

%e 4........................14,16

%e 5.....................18,10,12,20

%e 6.................22,14,6,2,4,8,16,24

%e 7..............26,18,10,6,2,4,8,12,20,28

%e 8..................30,22,14,16,24,32

%e 9........................34,36

%e 10....................38,26,28,40

%e 11..............42,30,18,10,12,20,32,44

%e 12..........46,34,22,14,6,2,4,8,16,24,36,48

%e 13.......50,38,26,18,10,6,2,4,8,12,20,28,40,52

%o (PARI) See Links section.

%Y Cf. A253028, A354576.

%K nonn,tabf

%O 1,1

%A _Felix Fröhlich_, May 30 2022