45156
domain: N
Appears in sequences
- Expansion of g.f. 1/(1-x-x^2-x^4-x^5).at n=19A079976
- First differences of A000043.at n=35A134458
- Intersection of A002378 and A135013.at n=6A135014
- Number of (n+2)X(n+2) binary arrays avoiding patterns 001 and 110 in rows, columns and nw-to-se diagonals.at n=6A202439
- Number of (n+2) X 9 binary arrays avoiding patterns 001 and 110 in rows, columns and nw-to-se diagonals.at n=6A202446
- Partial sums of A255745.at n=28A255766
- Oblong numbers the product of whose digits are positive oblong numbers.at n=16A285079
- Number of disconnected or empty antichains of nonempty subsets of {1..n} (non-spanning edge-connectivity 0).at n=6A327354
- Numbers that are the sum of seven fourth powers in nine or more ways.at n=22A345575
- Numbers that are the sum of seven fourth powers in exactly nine ways.at n=20A345831
- a(n) = (1/phi(n)) * Sum_{j=1..n} Sum_{k=1..n} phi(n*j*k).at n=21A372668