21599

Properties

Appears in sequences

• Smallest number of complexity n: smallest number requiring n 1's to build using + and *.at n=33A005520
• Numerator of [x^(2n+1)] of the Taylor expansion tanh(cosec(x) - cot(x)).at n=7A013524
• Primes p such that (p-1)/2 and (p-3)/4 are also prime.at n=29A066179
• a(n) is least k such that A077614(k)=n or 0 if there is none.at n=8A077615
• Primes p such that 5 is the largest of all prime factors of the numbers between p and the next prime (cf. A052248).at n=16A080185
• A000041(n) - A000203(n).at n=36A086738
• Primes of the form 6n^2 - 1.at n=23A090686
• Primes of the form 16*k-1 such that 4*k-1 and 8*k-1 are also primes.at n=16A101793
• Primes of the form 32*k-1 such that 4*k-1, 8*k-1 and 16*k-1 are also primes.at n=2A101798
• Primes p such that p + 2 and p*(p + 2) + 2 are primes.at n=38A108013
• Triple-safe primes p: p, (p-1)/2, (p-3)/4, and (p-7)/8 are all prime.at n=8A157358
• The lesser of twin prime pairs with each prime in a different century.at n=9A158277
• a(n) = 900*n - 1.at n=23A158409
• a(n) = 24*n^2 - 1.at n=29A158544
• a(n) = 54*n^2 - 1.at n=19A158656
• a(n) is the sum of the smallest parts of all partitions of n that do not contain 1 as a part.at n=41A182708
• Primes of the form n^2 - 10.at n=11A201313
• a(n) = prime(n*prime(n)).at n=24A228529
• 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=28A232238
• Positions of records in A249442.at n=10A249440