login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A340529
Irregular triangle read by rows T(n,k), (n >= 1, k >= 1), in which row n has length A000041(n-1) and every column k is A006218.
3
1, 3, 5, 1, 8, 3, 1, 10, 5, 3, 1, 1, 14, 8, 5, 3, 3, 1, 1, 16, 10, 8, 5, 5, 3, 3, 1, 1, 1, 1, 20, 14, 10, 8, 8, 5, 5, 3, 3, 3, 3, 1, 1, 1, 1, 23, 16, 14, 10, 10, 8, 8, 5, 5, 5, 5, 3, 3, 3, 3, 1, 1, 1, 1, 1, 1, 1, 27, 20, 16, 14, 14, 10, 10, 8, 8, 8, 8, 5, 5, 5, 5, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, 1, 1, 1, 1
OFFSET
1,2
FORMULA
a(m) = A006218(A336811(m)).
T(n,k) = A006218(A336811(n,k)).
EXAMPLE
Triangle begins:
1;
3;
5, 1;
8, 3, 1;
10, 5, 3, 1, 1;
14, 8, 5, 3, 3, 1, 1;
16, 10, 8, 5, 5, 3, 3, 1, 1, 1, 1;
20, 14, 10, 8, 8, 5, 5, 3, 3, 3, 3, 1, 1, 1, 1;
23, 16, 14, 10, 10, 8, 8, 5, 5, 5, 5, 3, 3, 3, 3, 1, 1, 1, 1, 1, 1, 1;
...
For n = 6, the length of row 6 is A000041(5) = 7.
The sum of row 6 is 14 + 8 + 5 + 3 + 3 + 1 + 1 = 35, equaling A006128(6).
CROSSREFS
Row sums give A006128.
Cf. A340525 (a regular version).
Members of the same family are: A336811, A339278, A339304, A340423.
Sequence in context: A236631 A302800 A367067 * A197326 A235605 A212695
KEYWORD
nonn,tabf
AUTHOR
Omar E. Pol, Jan 10 2021
STATUS
approved