login
A238956
Degree of divisor lattice in graded colexicographic order.
2
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
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:
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;
...
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.
Sequence in context: A344150 A128219 A238969 * A331415 A295511 A116505
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