42750

Appears in sequences

• a(n) = 225*(n-1)*(n-2)/2.at n=18A027470
• Numbers which can be expressed as the product of a number and its reversal in at least two different ways.at n=28A066531
• Expansion of eta(q^4)^2 / (eta(q^2) * eta(q)^6) in powers of q.at n=9A134416
• Number of nXnXn triangular 0..6 arrays with some element plus some adjacent element totalling 6 exactly once.at n=2A270255
• T(n,k)=Number of nXnXn triangular 0..k arrays with some element plus some adjacent element totalling k exactly once.at n=30A270256
• Number of 3X3X3 triangular 0..n arrays with some element plus some adjacent element totalling n exactly once.at n=5A270258
• G.f. = Phi^3*F^3, where Phi = g.f. for A028930, F = g.f. for A028959.at n=16A328534
• Number of excursions of length n with Motzkin-steps avoiding the consecutive steps UH, HD and DU.at n=20A329698
• Numbers k such that k and the least number that is larger than k and has the same prime signature as k also has the same set of distinct prime divisors as k.at n=39A340302
• Numbers k such that A065642(k) = A081761(k).at n=9A340306