22961

Properties

Appears in sequences

• Pisot sequence E(9,15), a(n) = floor( a(n-1)^2/a(n-2) + 1/2 ).at n=15A014003
• Primes of the form k^2 + k + 9.at n=18A027758
• Number of achiral polyominoes with n cells.at n=18A030227
• Partial sums of sequence (essentially A002378): 1, 2, 6, 12, 20, 30, 42, 56, 72, 90, ...at n=40A064999
• Primes of the form sum 6d/(2 + mu(d)) for some k and all d dividing k.at n=35A069548
• Final terms of rows of A077321.at n=40A077323
• Let n range through the odd numbers skipping multiples of 5; a(n) = n-th prime ending in n.at n=24A089779
• G.f.: 1/(1-2x-19x^2)^(1/2).at n=7A098264
• a(n) = 3*a(n-1) + 5 with a(0) = 1.at n=8A116952
• Primes in the sequence A003294 of certain fourth powers bases.at n=17A134820
• a(1) = 3. For n > 1, Ulam's spiral is started with a(n-1), and the primes p on the NE spoke are considered. a(n) is the minimal p that is the lesser of a twin prime pair.at n=28A163586
• Centered 28-gonal numbers.at n=40A195314
• Primes p such that floor(log(p)) + p^2 is prime.at n=21A225626
• Primes p with same last two digits as k, where prime(k) = p.at n=27A232102
• Primes p such that p+2 and q are primes, where q is concatenation of binary representations of p and p+2: q = p * 2^L + p+2, where L is the length of binary representation of p+2: L=A070939(p+2).at n=30A232238
• The prime(n)-th prime number ending in prime(n), or 0 if none exists.at n=17A238331
• Prime time primes (of the form HMMSS with primes H < 24 and MM, SS < 60) such that the corresponding number of seconds after midnight is also prime.at n=18A295000
• a(n) = N^(1/4) * log(N) / sqrt(log(log(N))) rounded to nearest integer, with N=2^n. Related to operation count of the deterministic factorization of an integer N using an improved Pollard-Strassen method.at n=40A309916
• Primes p such that p+2 is prime and p+A001414(p+1)+(p+2) is prime.at n=43A330488
• Square array read by antidiagonals upwards: T(n,k) for integer k >= 0 is the n-th prime p such that p^(2*3^k) + p^(3^k) + 1 is prime.at n=33A344448