40514

Appears in sequences

• Numbers k such that phi(k) + phi(k+1) = k+2.at n=23A067797
• Number of bipartite outerplanar graphs on n unlabeled nodes.at n=12A111759
• Numbers k such that Sum_{j=1..k} sigma(j) is a triangular number, where sigma(j) = sum of divisors of j (A000203).at n=8A226648
• The number of NE partitions of n (see Comments).at n=40A239329
• Number of (n+2)X(n+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 0 3 5 6 or 7 and every 3X3 column and antidiagonal sum not equal to 0 3 5 6 or 7.at n=10A252376
• Regular triangle read by rows where T(n, k) is the number of set partitions of {1, ..., n} requiring k steps of removing singletons and cyclical adjacency initiators until reaching a fixed point, n >= 0, 0 <= k <= n.at n=57A306418