27170

Appears in sequences

• a(n) = position of 3*n^3 in A003072.at n=43A024970
• a(n) = prime(n)*Catalan(n).at n=7A028302
• First numerator and then denominator of the central elements of the 1/3-Pascal triangle (by row).at n=18A046543
• First denominator and then numerator of the central elements of the 1/3-Pascal triangle (by row).at n=19A046544
• Distinct numbers in writing first numerator and then denominator of the central elements of the 1/3-Pascal triangle (by row).at n=9A046545
• Distinct even numbers in the numerators of the 1/3-Pascal triangle (by row).at n=37A046559
• a(n) = Sum_{i=0..floor(n/2)} T(i,n-i), array T as in A047072.at n=18A047074
• Numbers n such that sigma(n)/phi(n) is prime.at n=39A067780
• Squarefree balanced numbers (i.e., squarefree members of A020492).at n=42A078557
• a(n) = (-1)^n*(2*n - 1)*CatalanNumber(n - 2) for n >= 2, a(n) = n for n = 0, 1.at n=10A078718
• Number of prime pairs below 10^n having a difference of 24.at n=6A093747
• Take a <= b such that f(a)+f(b)=concatenation of a and b, where f(k)=k(k+3)/2 (A000096). Sequence gives values of b.at n=32A099149
• Maximal troughs in decimal expansions of Pi: positions of troughs equal to 8.at n=26A105276
• a(n) = A019565(n-th prime).at n=41A109163
• Numbers such that Sigma(m)*UnitarySigma(m)= k*UnitaryPhi(m)^2, for some integer k.at n=48A122839
• Numbers n such that sigma(n) = 7*phi(n).at n=10A136540
• Numbers m such that m^2 + 3^k is prime for k = 1, 2, 3.at n=38A177173
• Number of nX3 binary arrays without the pattern 0 0 1 vertically or antidiagonally.at n=5A189190
• T(n,k)=Number of nXk binary arrays without the pattern 0 0 1 vertically or antidiagonally.at n=33A189196
• Number of 6Xn binary arrays without the pattern 0 0 1 vertically or antidiagonally.at n=2A189199