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A238953
The size of divisor lattice D(n) in graded (reflected or not) colexicographic order of exponents.
4
0, 1, 2, 4, 3, 7, 12, 4, 10, 12, 20, 32, 5, 13, 17, 28, 33, 52, 80, 6, 16, 22, 24, 36, 46, 54, 72, 84, 128, 192, 7, 19, 27, 31, 44, 59, 64, 75, 92, 116, 135, 176, 204, 304, 448, 8, 22, 32, 38, 40, 52, 72, 82, 96, 104, 112, 148, 160, 186, 216, 224, 280, 324, 416, 480, 704, 1024
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) = A062799(A036035(n,k)).
EXAMPLE
Triangle T(n,k) begins:
0;
1;
2, 4;
3, 7, 12;
4, 10, 12, 20, 32;
5, 13, 17, 28, 33, 52, 80;
6, 16, 22, 24, 36, 46, 54, 72, 84, 128, 192;
...
PROG
(PARI) \\ here b(n) is A062799.
b(n)={sumdiv(n, d, omega(d))}
N(sig)={prod(k=1, #sig, prime(k)^sig[k])}
Row(n)={apply(s->b(N(s)), [Vecrev(p) | p<-partitions(n)])}
{ for(n=0, 6, print(Row(n))) } \\ Andrew Howroyd, Apr 25 2020
CROSSREFS
Cf. A062799 in graded colexicographic order.
Sequence in context: A166017 A257504 A207625 * A238964 A035507 A138612
KEYWORD
nonn,tabf
AUTHOR
Sung-Hyuk Cha, Mar 07 2014
EXTENSIONS
Offset changed and terms a(64) and beyond from Andrew Howroyd, Apr 25 2020
STATUS
approved

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