|
|
A037805
|
|
Number of i such that d(i) < d(i-1), where Sum_{i=0..m} d(i)*7^i is the base-7 representation of n.
|
|
2
|
|
|
0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 1, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 2
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,66
|
|
LINKS
|
|
|
MAPLE
|
a := 0 ;
dgs := convert(n, base, 7);
for i from 2 to nops(dgs) do
if op(i, dgs)<op(i-1, dgs) then
a := a+1 ;
end if;
end do:
a ;
|
|
PROG
|
(PARI) a(n) = {my(d = Vecrev(digits(n, 7))); my(dd = vector(#d-1, k, d[k+1] - d[k])); #select(x->(x<0), dd); } \\ Michel Marcus, Oct 16 2015
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,base
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|