OFFSET
1,2
COMMENTS
The string can be too short to have either 3 total 2's or 4 total 1's, because the batter can be out in various ways, or on base in various ways (hit by pitched ball, balk) before the at-bat ends with strikout or walk. A proper subset of A007931.
LINKS
Jonathan Vos Post, Mar 31 2008, Table of n, a(n) for n = 1..63
EXAMPLE
a(14) = 222 represents a strikeout in 3 consecutive pitches. a(15) = 1111 represents a walk in 4 consecutive pitches.
2221 is the lexicographically earliest element of A007931 not in this sequence, since after 3 strikes the batter is out and there is no 4th pitch in the at-bat.
11111 is the lexicographically earliest element of A007931 without a 2 not in this sequence, since after 4 balls the batter walks and there is no 5th pitch in the at-bat. Technically, this sequence contains the null string (the batter is out without a pitch being thrown, in several ways) but that is not properly represented as a string of 1s and 2s in the OEIS.
CROSSREFS
KEYWORD
base,easy,fini,nonn
AUTHOR
Jonathan Vos Post, Mar 31 2008
STATUS
approved