20107

Properties

Appears in sequences

• a(n) = Sum_{k=1..n} C(n, floor(n/k)).at n=16A051054
• Denominators of convergents to Pi by Farey fractions.at n=45A063673
• Initial term in sequence of four consecutive primes whose consecutive differences have d-pattern = [6, 4, 6]; short d-string notation for pattern = [646].at n=26A078856
• Primes p such that the differences between the 5 consecutive primes starting with p are (6,4,6,6).at n=7A078964
• Primes in A051022.at n=31A092908
• Ceiling(4*Pi*n^2).at n=39A135971
• Primes p such that p - 6^2, p - 6, p + 6 and p + 6^2 are also primes.at n=37A141279
• Primes p such that p-6^3, p-6^2, p-6, p, p+6, p+6^2 and p+6^3 are primes.at n=8A141280
• Primes congruent to 38 mod 61.at n=39A142836
• Primes p such that p^2 - 2 is a 5-almost prime.at n=32A156620
• Primes p such that 8*p^2-2*p-1 divides Fibonacci(p).at n=17A159231
• Row 4 of table A162424.at n=26A162427
• Primes of form 5+38*n^2.at n=17A173554
• a(n) is the smallest prime such that it and the previous two primes are all of the form x^2 + n * y^2.at n=38A212603
• Balanced primes which are the average of two successive semiprimes.at n=16A212820
• Primes p with pi(p) and pi(p^2) both prime, where pi(.) is given by A000720.at n=29A237659
• Primes which are the average of the two adjacent primes and also of the two adjacent squarefree numbers.at n=22A245589
• Primes whose decimal expansion is of the form d_1+0+d_2+0+d_3+0+...+0+d_k where d_i are digits with 1 <= d_i <= 9, k > 1 and + stands for concatenation.at n=25A309488
• Numbers k such that 329*2^k+1 is prime.at n=25A322957
• Prime numbers representing a date based on the proleptic Gregorian calendar in YY..YMMDD format.at n=33A352947