A238956 - OEIS

A238956

Degree of divisor lattice in graded colexicographic order.

0, 1, 2, 2, 2, 3, 3, 2, 3, 4, 4, 4, 2, 3, 4, 4, 5, 5, 5, 2, 3, 4, 4, 4, 5, 6, 5, 6, 6, 6, 2, 3, 4, 4, 4, 5, 5, 6, 5, 6, 7, 6, 7, 7, 7, 2, 3, 4, 4, 4, 4, 5, 5, 6, 6, 5, 6, 6, 7, 8, 6, 7, 8, 7, 8, 8, 8, 2, 3, 4, 4, 4, 4, 5, 5, 5, 6, 6, 6, 5, 6, 6, 7, 7, 8, 6, 7, 7, 8, 9, 7, 8, 9, 8, 9, 9, 9

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..2713 (rows 0..20)

S.-H. Cha, E. G. DuCasse, and L. V. Quintas, Graph Invariants Based on the Divides Relation and Ordered by Prime Signatures, arxiv:1405.5283 [math.NT], 2014.

FORMULA

T(n,k) = A238949(A036035(n,k)).

EXAMPLE

Triangle T(n,k) begins:

2, 2;

2, 3, 3;

2, 3, 4, 4, 4;

2, 3, 4, 4, 5, 5, 5;

2, 3, 4, 4, 4, 5, 6, 5, 6, 6, 6;

...

PROG

(PARI)

C(sig)={sum(i=1, #sig, if(sig[i]>1, 2, 1))}

Row(n)={apply(C, [Vecrev(p) | p<-partitions(n)])}

{ for(n=0, 8, print(Row(n))) } \\ Andrew Howroyd, Apr 01 2020

CROSSREFS

Cf. A238949 in graded colexicographic order.

Cf. A036035, A238969.

Sequence in context: A344150 A128219 A238969 * A331415 A295511 A116505

Adjacent sequences: A238953 A238954 A238955 * A238957 A238958 A238959

KEYWORD

nonn,tabf

AUTHOR

Sung-Hyuk Cha, Mar 07 2014

EXTENSIONS

Offset changed and terms a(50) and beyond from Andrew Howroyd, Apr 01 2020

STATUS

approved