21858

Appears in sequences

• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (1, p(1), p(2), ...), t = (composite numbers).at n=38A024480
• Numbers m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,39.at n=4A064256
• (1, 3, 5, 7, 9, ...) convolved with (1, 0, 3, 5, 7, 9, ...).at n=32A179903
• Number of nondecreasing -n..n vectors of length 3 whose dot product with some nondecreasing -n..n vector equals 3.at n=25A226411
• Number of n X 6 0..2 arrays with no element equal to one plus the sum of elements to its left or one plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest, modulo 3.at n=22A239359
• Number of n-node rooted trees of height 10.at n=6A245068
• Number of integer partitions of n with a permutation that has no consecutive monotone triple, i.e., no triple (..., x, y, z, ...) such that either x <= y <= z or x >= y >= z.at n=39A344740
• Number of integer partitions of n with an alternating permutation.at n=39A345170
• Table read by antidiagonals: T(t,n) = number of t-metered parking functions of length n.at n=41A372816
• Table read by antidiagonals: T(m,n) = number of 4-metered (m,n)-parking functions.at n=60A372820
• Table read by antidiagonals: T(m,n) = number of (m-2)-metered (m,n)-parking functions.at n=60A372821
• Number of achiral planar maps with n vertices and 2 faces.at n=12A380238
• a(n) is the number of 5 element sets of distinct integer-sided trapezoids whose base angles are 60 degrees that fill an equilateral triangular grid of side n units with a trapezoid filled by 3 trapezoids.at n=27A391204