20505

Appears in sequences

• Number of maximal collections of pairwise disjoint subsets {X,Y,Z} of {1, 2, ..., n} with X + Y = Z (as in A002849), with the property that n is in one of the subsets.at n=27A002848
• Number of maximal collections of pairwise disjoint subsets {X,Y,Z} of {1, 2, ..., n}, each satisfying X + Y = Z.at n=26A002849
• Base-9 palindromes that start with 3.at n=30A043030
• a(n) = Sum_{k=1..n} A060999(k) * k^3.at n=6A061000
• Number of partitions of {1,2,...,3n} into n triples (X,Y,Z) each satisfying X+Y=Z.at n=9A108235
• Numbers k such that k and k^2 use only the digits 0, 2, 3, 4 and 5.at n=40A136882
• Numbers k such that k and k^2 use only the digits 0, 2, 4 and 5.at n=27A136897
• Numbers k such that k and k^2 use only the digits 0, 2, 4, 5 and 6.at n=48A136898
• Numbers k such that k and k^2 use only the digits 0, 2, 4, 5 and 7.at n=39A136899
• Numbers k such that k and k^2 use only the digits 0, 2, 4, 5 and 8.at n=44A136900
• Numbers k such that k and k^2 use only the digits 0, 2, 4, 5 and 9.at n=42A136901
• Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0) and consisting of n steps taken from {(-1, 0), (0, -1), (1, 1)}.at n=11A151265
• Number of binary strings of length n with equal numbers of 0000 and 0101 substrings.at n=16A164150
• Difference between the number of odd parts and the number of even parts in all the partitions of n.at n=30A209423
• Number of different optimal triangle difference sets M(n,2).at n=8A234947
• The number of tilings of an 8 X (3n) floor with 2 X 3 hexominoes.at n=10A236583
• Number of length 4 1..(n+2) arrays with no leading partial sum equal to a prime and no consecutive values equal.at n=15A255719
• Numbers k such that {k + 2, k + 4} and {k^2 + 2, k^2 + 4} are both twin prime pairs.at n=12A284014
• A condensed version of A108235.at n=5A284737
• Numerators of Harary index for the n-Mycielski graph.at n=7A296193