27231

Appears in sequences

• Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 55.at n=2A031733
• Numbers k such that phi(k) = phi(k-2) - phi(k-1).at n=3A066232
• Numbers n such that sigma(n)=phi(n*bigomega(n)-1).at n=38A067877
• Markoff numbers (A002559) multiplied by 3.at n=20A086326
• Triangle read by rows: Catalan triangle of the k-Fibonacci sequence.at n=63A236918
• Convolution triangle of A000958(n+1).at n=57A237596
• Number of chiral immersions of oriented circle into oriented sphere with 2n double points.at n=4A268566
• a(n) is the row of the Trithoff (tribonacci) array that contains the tails of the sequence which is n times the tribonacci numbers.at n=34A351685
• a(n) = index of 2*prime(n) in A381019.at n=37A379811
• G.f. satisfies A(x) = -(A(x^3) + A(x^4)) / A(-x^2).at n=50A385915