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A274919
Sum of all perimeters of all parts of the symmetric representation of sigma(n).
4
4, 8, 12, 16, 16, 24, 20, 32, 32, 40, 28, 48, 32, 52, 52, 64, 40, 72, 44, 80, 72, 76, 52, 96, 68, 88, 88, 112, 64, 120, 68, 128
OFFSET
1,1
COMMENTS
a(n) is also the number of toothpicks added at n-th stage in the toothpick structure of the symmetric representation of sigma in two quadrants (without the axis x and y).
FORMULA
a(n) = 4*A244361(n) = 2*A244363(n) = A244371(n)/2.
a(n) = A008586(n) - 2*A279228(n). - Omar E. Pol, May 04 2023
EXAMPLE
Illustration of a(9) = 32:
. 12
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. _ _ 8
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. | | 12
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For n = 9 the symmetric representation of sigma(9) = 13 has three parts of areas 5, 3, 5 respectively. The perĂ­meters of the parts are 12, 8 and 12 as shown above. The sum of the perimeters is 12 + 8 + 12 = 32, so a(9) = 32.
KEYWORD
nonn,more
AUTHOR
Omar E. Pol, Dec 11 2016
EXTENSIONS
a(29)-a(32) from Omar E. Pol, May 04 2023
STATUS
approved