A295423 -id:A295423 - cp's OEIS frontend

A377462 a(n) is the size of the central part of the symmetric representation of sigma(n), or 0 if such a part does not exits.

1, 3, 0, 7, 0, 12, 0, 15, 3, 0, 0, 28, 0, 0, 8, 31, 0, 39, 0, 42, 0, 0, 0, 60, 5, 0, 0, 56, 0, 72, 0, 63, 0, 0, 12, 91, 0, 0, 0, 90, 0, 96, 0, 0, 32, 0, 0, 124, 7, 15, 0, 0, 0, 120, 0, 120, 0, 0, 0, 168, 0, 0, 16, 127, 0, 144, 0, 0, 0, 36, 0, 195, 0, 0, 0, 0, 18, 0, 0, 186, 9, 0, 0, 224, 0

Offset: 1

Omar E. Pol, Oct 29 2024

nonn

a(n) = A000203(n) if and only if n is a member of A174973.

			For n = 9 the symmetric representation of sigma(9) = 13 in the first quadrant looks like this:
y
.
._ _ _ _ _ 5
|_ _ _ _ _|
.         |_ _ 3
.         |_  |
.           |_|_ _ 5
.               | |
.               | |
.               | |
.               | |
. . . . . . . . |_| . . x
.
There are three parts [5, 3, 5] and the central part is 3 so a(9) = 3.

Indices of odd terms give A028982.
Indices of even terms give A028983.
Indices of zeros give A071561.
Indices of nonzero terms give A071562.
Nonzero terms give A295423.
Parity gives A053866.
Has the same parity as A000203, A000593, A001227, A033879, A033880, A067742.
Cf. A174973, A196020, A235791, A236104, A237270, A237271, A237591, A237593, A241558, A241559, A245092, A262626, A347950.

cp's OEIS Frontend

A377462 a(n) is the size of the central part of the symmetric representation of sigma(n), or 0 if such a part does not exits.

Views

Author

Keywords

Comments

Examples

Crossrefs