39790

Appears in sequences

• Number of permutations of length n which avoid the patterns 1234, 2413, 3241.at n=10A116747
• INVERT transform of phi(n), A000010.at n=14A159929
• Number of 6-step one space for components leftwards or up, two space for components rightwards or down asymmetric quasi-bishop's tours (antidiagonal moves become knight moves) on an n X n board summed over all starting positions.at n=12A187610
• Numbers k such that in a rotated-square spiral with positive integers (A215468) among k's eight nearest neighbors five or more are primes.at n=16A215471
• Numbers k such that if x = sigma(k) + tau(k) - k then k = sigma(x) + tau(x) - x.at n=27A238226
• Numbers m such that psi(x) = phi(m) has a solution while sigma(y) = phi(m) has none.at n=37A291524
• Greater members of dihedral amicable pairs: numbers (m, k) such that t(m) = t(k) = m + k, where t(k) = sigma(k) + d(k).at n=7A322254
• Number of permutations of [n] that avoid the shuffle pattern s-k-t, where s = 123 and t = 123.at n=8A324137
• The number of edges on a vesica piscis formed by the straight line segments mutually connecting all vertices and all points that divide the sides into n equal parts.at n=13A342152
• Expansion of (1/x) * Series_Reversion( x * (1-x)^2 / (1+x^2) ).at n=7A369208