23137

Appears in sequences

• Strong pseudoprimes to base 63.at n=21A020289
• a(n) = T(n,2n-8), T given by A027023.at n=9A027032
• Interprimes which are of the form s*prime, s=17.at n=11A075292
• a(n) = 2*a(n-1) + 7*a(n-2).at n=7A083100
• a(n) = 2*a(n-1) + 7*a(n-2) for n>1, a(0)=1, a(1)=1.at n=8A084058
• Number of primes with digit sum n having at most n digits.at n=10A110742
• Eigensequence of triangle A085478: a(n) = Sum_{k=0..n-1} A085478(n-1,k)*a(k) for n > 0 with a(0) = 1.at n=8A125273
• Eigentriangle of A085478: T(n,k) = A085478(n,k) * A125273(k).at n=44A144250
• a(0)=1, a(1)=9, a(n) = 18*a(n-1) - 49*a(n-2) for n > 1.at n=4A165224
• Numbers with d digits (d>0) which have at least 2d distinct primes as substrings.at n=20A168167
• Quartan semiprimes: semiprimes of the form x^4 + y^4, x>0, y>0.at n=18A182277
• Eigentriangle of triangle A085478.at n=36A186023
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 397", based on the 5-celled von Neumann neighborhood.at n=32A271691
• Indices of records in A288818.at n=9A288820
• Numbers k for which rank of the elliptic curve y^2=x^3-k*x is 4.at n=18A309034
• Number of steps needed to solve the Towers of Hanoi exchanging disks puzzle with 3 pegs and n disks.at n=16A341579
• a(n) is the numerator of Sum_{k = 0..n} fusc(k)/fusc(k+1) (where fusc is Stern's diatomic series A002487).at n=22A355075
• Numbers k such that k, k+1, k+2, k+3 have 2, 3, 4, 5 prime factors respectively, counted with multiplicity.at n=28A363391
• Triangular array T(n, k) read by rows: denominators of the coefficients for the iterated exponential F^{r}(x) = x + Sum_{n>=1} x^(n+1)*Sum_{k=1..n} r^(n+1-k)*T(n, k)/A381931(n, k) with F^{1}(x) = exp(x)-1 and F^{2}(x) = exp(exp(x)-1)-1.at n=42A381932
• Consecutive states of the linear congruential pseudo-random number generator 20403*s mod 2^15 when started at s=1.at n=24A384196