[go: up one dir, main page]

login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Revision History for A278984 (Bold, blue-underlined text is an addition; faded, red-underlined text is a deletion.)

Showing entries 1-10 | older changes
Array read by antidiagonals downwards: T(b,n) = number of words of length n over an alphabet of size b that are in standard order.
(history; published version)
#34 by N. J. A. Sloane at Wed Jul 01 23:33:12 EDT 2020
STATUS

proposed

approved

#33 by Wesley Ivan Hurt at Wed Jun 24 14:30:28 EDT 2020
STATUS

editing

proposed

#32 by Wesley Ivan Hurt at Wed Jun 24 14:30:24 EDT 2020
COMMENTS

We say that a word is in "standard order" if it has the property that whenever a letter i appears, the letter i-1 has already appeared in the word. This implies that all words begin with the letter 1.

STATUS

proposed

editing

#31 by Michel Marcus at Wed Jun 24 00:27:04 EDT 2020
STATUS

editing

proposed

#30 by Michel Marcus at Wed Jun 24 00:26:59 EDT 2020
COMMENTS

Let X be the random variable that assigns to each permutation of {1,2,...,b} (with uniform distribution) its number of fixed points (as in A008290). Then T(b,n) is the n^-th moment about 0 of X, i.e., the expected value of X^n. - Geoffrey Critzer, Jun 23 2020

STATUS

proposed

editing

#29 by Geoffrey Critzer at Tue Jun 23 13:17:06 EDT 2020
STATUS

editing

proposed

#28 by Geoffrey Critzer at Tue Jun 23 13:16:28 EDT 2020
COMMENTS

Let X be the random variable that assigns to each permutation of {1,2,...,b} (with uniform distribution) its number of fixed points (as in A008290). Then T(b,n) is the n^th moment about 0 of X, i.e., the expected value of X^n. - Geoffrey Critzer, Jun 23 2020

STATUS

approved

editing

#27 by N. J. A. Sloane at Sun Mar 19 19:27:53 EDT 2017
STATUS

proposed

approved

#26 by Andrew Howroyd at Sun Mar 19 17:46:43 EDT 2017
STATUS

editing

proposed

#25 by Andrew Howroyd at Sun Mar 19 17:36:05 EDT 2017
LINKS

Andrew Howroyd, <a href="/A278984/b278984.txt">Table of n, a(n) for n = 1..1275</a>

CROSSREFS

Rows 1 through 10 16 of the array are: A000012, A000079, A007051, (or A124302), A007581 (or A124303), A056272, A056273, A099262, A099263, A164863, A164864, A203641-A203646.

Cf. A203647, A137855 (essentially same table).

STATUS

approved

editing