23326

Appears in sequences

• a(n) = 2*prime(n)*prime(n+1).at n=27A069486
• Numbers n such that sum of distinct primes dividing n is divisible by the largest prime dividing n. Also n is neither a prime, nor a true power of prime and n is squarefree. Squarefree solutions of A071140.at n=25A071141
• Numbers of the form 2*p*q where (p,q) is a twin prime pair.at n=9A071142
• Squarefree numbers k such that the largest prime factor of k is equal to the sum of the other prime factors of k.at n=24A071312
• Squarefree numbers k such that A076341(k) = 0.at n=13A076352
• Numbers k = p*q*r (p, q, r prime) congruent to 0 mod p+q+r.at n=28A160394
• G.f.: exp( Sum_{n>=1} x^n/n * Product_{k>=1} (1 + x^(n*k)*(1 + x^k)^n) ).at n=19A218576
• a(n) = smallest index m such that smallest prime factor of m-th triangular number is prime(n).at n=27A226442
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 675", based on the 5-celled von Neumann neighborhood.at n=25A273408
• Numbers k such that sigma(k) = sigma(k - d(k)).at n=27A277273
• Numbers k such that Fibonacci(k) == +-1 (mod k) and k is neither 1 nor prime nor twice a prime.at n=29A279072
• Decimal representation of the x-axis, from the left edge to the origin, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 433", based on the 5-celled von Neumann neighborhood.at n=17A282201
• a(n) is the largest integer x such that x/sopf(x) = prime(n) where sopf(x) is the sum of distinct prime factors of x and prime(n) is the n-th prime.at n=27A336493
• a(1) = 12; for n >= 2, a(n) = least positive integer of the form prime(m)*prime(n-m)*prime(n) with m >= 1.at n=28A364434