A279667 Number of subparts (also number of odd divisors) of the smallest number k such that the symmetric representation of sigma(k) has n layers.

1, 2, 4, 4, 6, 8, 8, 12, 12, 12, 16, 24, 24, 18, 32, 32, 24, 36, 24, 36, 32, 48, 36, 32, 48, 48, 48

Offset

1,2

Comments

In other words: number of subparts (also number of odd divisors) of the smallest number k such that the symmetric representation of sigma(k) has at least a part of width n.

Note that the number of subparts in the symmetric representation of sigma(n) equals A001227(n), the number of odd divisors of n.

For more information about the subparts and the layers see A279387.

Links

Table of n, a(n) for n=1..27.

Formula

a(n) = A001227(A250070(n)).

Example

For n = 5 we have that 360 is the smallest number k whose symmetric representation of sigma(k) has parts of width 5. The structure has six subparts: [719, 237, 139, 71, 2, 2]. On the other hand, 360 has six odd divisors: {1, 3, 5, 9, 15, 45}, so a(5) = 6.

Crossrefs

Cf. A000203, A001227, A005279, A196020, A236104, A235791, A237048, A237270, A237271, A237591, A237593, A239657, A244050, A245092, A250070, A261699, A279387, A279388, A279391.

Sequence in context: A063200 A063224 A023847 * A000061 A153176 A229144

Adjacent sequences: A279664 A279665 A279666 * A279668 A279669 A279670

Keyword

nonn,more

Author

Omar E. Pol, Dec 16 2016

Status

approved