87780

Appears in sequences

• a(n) = n*(n + 1)*(n + 2)*(n + 3)/2.at n=19A033486
• a(n) = n*(2*n-1)*(2*n+1).at n=28A035328
• Numbers k such that usigma(k) is a square and sets a new record for such squares.at n=36A064443
• a(n) = binomial(2*n, n) mod ((n+1)*(n+2)*(n+3)*(n+4)).at n=17A065346
• Numbers k such that phi(k) < k/5.at n=8A066765
• Numbers with six distinct prime divisors.at n=18A074969
• a(n) = C(1+n,1) * C(2+n,1) * C(4+n,2).at n=18A112415
• Riordan array [(1-x)exp(x/(1-x)),x].at n=48A152151
• Numerator of Euler(n, 3/31).at n=4A157530
• a(n) = the smallest positive integer that, when written in binary, contains both binary n and binary n^2 as substrings.at n=41A165820
• Numbers k such that bigomega(k)^omega(k) > k.at n=38A177871
• Numbers with prime factorization pqrstu^2.at n=2A189985
• Numbers k such that both k and k^2 are sums of a twin prime pair.at n=16A213784
• Integer area of primitive bicentric quadrilateral with integer side, rational inradius and rational circumradius. Excluding right kites.at n=2A273752
• Number of nX4 0..2 arrays with no element equal to any value at offset (-1,-1) (-2,0) or (0,-2) and new values introduced in order 0..2.at n=5A274955
• Number of nX6 0..2 arrays with no element equal to any value at offset (-1,-1) (-2,0) or (0,-2) and new values introduced in order 0..2.at n=3A274957
• T(n,k)=Number of nXk 0..2 arrays with no element equal to any value at offset (-1,-1) (-2,0) or (0,-2) and new values introduced in order 0..2.at n=39A274959
• T(n,k)=Number of nXk 0..2 arrays with no element equal to any value at offset (-1,-1) (-2,0) or (0,-2) and new values introduced in order 0..2.at n=41A274959
• Triangle where g.f. S = S(x,m) satisfies: S = x/(G(-S^2)*G(-m*S^2)) such that G(x) = 1 + x*G(x)^2 is the g.f. of the Catalan numbers (A000108), as read by rows of coefficients T(n,k) of x^(2*n-1)*m^k in S(x,m) for n>=1, k=0..n-1.at n=48A278880
• Triangle where g.f. S = S(x,m) satisfies: S = x/(G(-S^2)*G(-m*S^2)) such that G(x) = 1 + x*G(x)^2 is the g.f. of the Catalan numbers (A000108), as read by rows of coefficients T(n,k) of x^(2*n-1)*m^k in S(x,m) for n>=1, k=0..n-1.at n=51A278880