OFFSET
1,2
COMMENTS
Previous name: Row numbers that set records for initial gap lengths g in the permutations found in A088643.
LINKS
J. W. Roche, Letter regarding "M. J. Kenney and S. J. Bezuszka, Calendar problem 12, 1997", Mathematics Teacher, 91 (1998), 155.
EXAMPLE
For n = 4, when we examine row 13 in A088643, the Roche algorithm produces the initial row values 13, 10, 9, 8, 11, 12. The remaining values are equal to row 7 in A088643, and at no earlier point in row 13 are the remaining values equal to row m, 7 < m < 13. So we calculate the difference between 13 and 7 ("the uncharted length") to be 6, which is longer than the previous record uncharted length (A049478(3) = 4) set by row a(3) = 5. So a(4) = 13. - Peter Munn, Aug 03 2021 (based on text supplied by J. Stauduhar)
PROG
(PARI) {print1(m=0); for( n=1, oo, my( r=A088643_row(n)); for( g=1, #r-1, if( Set(r[1..g]) == [n-g+1..n] && r[g+1]==n-g, g > m && print1(", "n)+ m=g; break)))} \\ M. F. Hasler, Aug 04 2021
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
EXTENSIONS
Revised by Sean A. Irvine, Aug 03 2021
STATUS
approved