20687

Appears in sequences

• Denominators of continued fraction convergents to sqrt(271).at n=11A041509
• Composite numbers n such that sigma(n+24) = sigma(n) + 24.at n=19A054983
• a(n) = prime(n)*prime(n+3).at n=32A090090
• Numbers k such that 2^k + 3*k is prime.at n=20A093988
• Values of b such that (c+9b)*prime(n)#-1 is the least prime such that (c+kb)*prime(n)#-1 are all primes for 0 <= k <= 9, or 0 if there is no solution with c+9b < prime(n)#.at n=26A188367
• Number of (n+1) X (n+1) 0..2 arrays with every 2 X 2 subblock having one or three distinct values, and new values 0..2 introduced in row major order.at n=2A210099
• Number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock having one or three distinct values, and new values 0..2 introduced in row major order.at n=2A210102
• T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with every 2X2 subblock having one or three distinct values, and new values 0..2 introduced in row major order.at n=12A210107
• S_9 sequence in partition of integers > 1 described in A240521.at n=39A240536
• Positive fundamental solution y(n) of the generalized Pell equation X^2 - D(n) Y(n) = 2 with D(n) = A261246(n).at n=29A261248
• Sequence of pairwise relatively prime numbers of class P_6 (see comment in A275246).at n=17A275251
• y-value of the smallest solution to x^2 - p*y^2 = 2*(-1)^((p+1)/4), p = A002145(n).at n=30A306566
• Incrementally largest values of minimal y satisfying the equation x^2 - D*y^2 = 2, where D is a prime number.at n=6A336789