|
| |
|
|
A137741
|
|
Number of different strings of length n+4 obtained from "123...n" by iteratively duplicating any substring.
|
|
3
| |
|
|
1, 16, 54, 119, 218, 360, 555, 814, 1149, 1573, 2100, 2745, 3524, 4454, 5553, 6840, 8335, 10059, 12034, 14283
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| See A137743 for comments and examples.
|
|
|
LINKS
| Index entries for doubling substrings
|
|
|
FORMULA
| a(n)=n^4 for n=1,2; a(n)=1/24*(n+3)*(n^3+15*n^2+50*n-96) for n>2 (conjectured).
|
|
|
PROG
| (PARI) A137741(n)=if(n<2, 1, n=A135473(n+4, n); n[ #n]) /* function A135473 defined in A137743 */
(PARI) A137741(n)=if(n<3, n^4, 1/24*(n+3)*(n^3+15*n^2+50*n-96)) /* conjectured */
|
|
|
CROSSREFS
| Cf. A137740-A137743, A135473, A137744-A137748.
Sequence in context: A164324 A197246 A187104 * A167690 A172190 A122658
Adjacent sequences: A137738 A137739 A137740 * A137742 A137743 A137744
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| M. F. Hasler (www.univ-ag.fr/~mhasler), Feb 10 2008
|
| |
|
|
