21673

Properties

Appears in sequences

• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 78 ones.at n=31A031846
• Molien series for group G_{1,2}^{8} of order 1536.at n=36A051462
• Centered 24-gonal numbers.at n=42A069190
• Sum of GCD's of parts in all partitions of n.at n=36A078392
• Binomial transform of a Jacobsthal convolution.at n=8A084153
• Expansion of 1/sqrt((1-x)^2-8x^4).at n=15A098483
• Primes p such that p + googol is prime.at n=16A108250
• Primes that can be written as a sum of a positive square and a positive cube in more than one way.at n=36A162930
• Primes which are the sum of three distinct positive cubes in two or more distinct ways.at n=18A180088
• Primes expressed as the sum of square of digits of all primes.at n=28A181508
• Primes p such that p^2 divides 2^(2^(p-1)-1) - 1.at n=26A188465
• Primes of the form 3*m^2 - 2.at n=13A201715
• Floor(sqrt(7*2^n)).at n=26A221943
• Sum of largest parts of all partitions of n into an even number of parts.at n=29A222048
• Primes whose base-7 representation also is the base-3 representation of a prime.at n=25A235470
• Primes p such that p^2 + 4 and p^2 + 10 are also primes.at n=42A237890
• a(n) = prime(k-1) with k = n^2 + prime(n)^2.at n=14A243893
• Numbers n for which the numbers 6n+1, 3n+2, 6n+7 are all odd composite squarefree numbers, but none are semiprimes.at n=36A263510
• Odd k for which abs(2^m - k) is nonprime for all m < k.at n=12A263865
• Decimal representation of the middle column of the "Rule 137" elementary cellular automaton starting with a single ON (black) cell.at n=14A267515