OFFSET
0,3
COMMENTS
Row lengths are given by Pascal's triangle (cf. A007318), seen as flattened sequence, or for n > 0: length of n-th row = A007318(A003056(n-1),A002262(n-1));
1 <= i < j <= length of n-th row: A023416(T(n,i)) = A023416(T(n,j)), A000120(T(n,i)) = A000120(T(n,j)) and A070939(T(n,i)) = A070939(T(n,j));
the table provides a permutation of the natural numbers when seen as flattened sequence.
LINKS
Reinhard Zumkeller, Rows n = 0..78 of triangle, flattened - all terms < 2^12
Reinhard Zumkeller, Illustration of initial terms
EXAMPLE
See link.
PROG
(Haskell)
import List (elemIndices)
a187769 n k = a187769_tabf !! n !! k
a187769_row n = a187769_tabf !! n
a187769_tabf = [0] : [elemIndices (b, len - b) $
takeWhile ((<= len) . uncurry (+)) $ zip a000120_list a023416_list |
len <- [1 ..], b <- [1 .. len]]
a187769_list = concat a187769_tabf
CROSSREFS
KEYWORD
nonn,base,tabf
AUTHOR
Reinhard Zumkeller, Jan 05 2013
STATUS
approved