18261

Appears in sequences

• MacMahon's generalized sum of divisors function.at n=22A002128
• a(0) = 1, a(n) = 19*n^2 + 2 for n>0.at n=31A010009
• Maximal elements of pairs of "Super Unitary Amicable Numbers", sorted by their minimal elements.at n=33A045614
• Number of walks of length n between adjacent nodes on the Petersen graph.at n=11A091001
• Riordan array (1/sqrt(1-2*x-3*x^2), M(x)-1) where M(x) is the g.f. of the Motzkin numbers A001006.at n=58A114422
• Numbers k such that the decimal digits of phi(k) are a permutation of those of k.at n=23A115921
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, -1), (0, -1, 1), (0, 1, 0), (1, 0, -1)}.at n=11A148081
• a(n) = A013928(A002110(n)).at n=6A158341
• Number of permutations of 1..n containing the relative rank sequence { 316524 } at any spacing.at n=3A159170
• Partial sums of A160120.at n=42A162778
• Number of partitions p of n such that neither floor(mean(p)) nor ceiling(mean(p)) is a part.at n=44A241343
• Row sums of A259701 except first column.at n=12A259702
• Number of chair trees constructed from n chairs.at n=7A292097
• Numbers k such that sigma(k) - k - 1 is a perfect number.at n=7A293992
• Solution of the complementary equation a(n) = 2*a(n-1) - a(n-2) + b(n-1) -2, where a(0) = 1, a(1) = 2, b(0) = 3, and (a(n)) and (b(n)) are increasing complementary sequences.at n=45A294868
• Partial sums of A299254.at n=22A299260
• Number of quadrilateral regions in an equilateral triangular "frame" of size n (see Comments in A328526 for definition).at n=15A333033
• Triangle read by rows: T(n,k) is the number of face-connected components of polyhedra with k prisms and n-k truncated cuboctahedra in the omnitruncated cubic honeycomb up to translation and rotation, 0 <= k <= n.at n=23A384756