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A273978 List of words of length n over an alphabet of size 9 that are in standard order and which have the property that every letter that appears in the word is repeated. 2
11, 111, 1111, 1122, 1212, 1221, 11111, 11122, 11212, 11221, 11222, 12112, 12121, 12122, 12211, 12212, 12221, 111111, 111122, 111212, 111221, 111222, 112112 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

We study words made of letters from an alphabet of size b, where b >= 1. (Here b=9.) We assume the letters are labeled {1,2,3,...,b}. There are b^n possible words of length n.

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.

These are the words described in row b=9 of the array in A278987.

REFERENCES

D. D. Hromada, Integer-based nomenclature for the ecosystem of repetitive expressions in complete works of William Shakespeare, submitted to special issue of Argument and Computation on Rhetorical Figures in Computational Argument Studies, 2016.

LINKS

Daniel Devatman Hromada, Table of n, a(n) for n = 1..4360

Joerg Arndt and N. J. A. Sloane, Counting Words that are in "Standard Order"

PROG

#PERL checking whether numbers listed in A273977 and given in standard input belong to the current sequence

OUTER: while (<>) {

my %d;

$i=$_;

chop $i;

for $d (split //, $i) {

(exists $d{$d}) ? ($d{$d}++) : ($d{$d}=1);

}

for $k (keys %d) {

next OUTER if ($d{$k}<2);

}

print "$i\n";

}

CROSSREFS

Subset of A273977.

Cf. A278987.

Sequence in context: A265380 A114397 A098595 * A077488 A039988 A182452

Adjacent sequences:  A273975 A273976 A273977 * A273979 A273980 A273981

KEYWORD

base,easy,nonn

AUTHOR

Daniel Devatman Hromada, Nov 10 2016

EXTENSIONS

Edited by N. J. A. Sloane, Dec 06 2016

STATUS

approved

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Last modified November 17 03:06 EST 2019. Contains 329216 sequences. (Running on oeis4.)