19213

Properties

Appears in sequences

• Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 21.at n=6A031609
• Primes p such that the decimal digits of p^2 can be partitioned into two or more nonzero squares.at n=35A048646
• Prime(n) and prime(n+2) use the same digits.at n=26A069794
• a(n) = A000040(A096480(n)).at n=28A096481
• Numbers k such that k and k^2 use only the digits 1, 2, 3, 6 and 9.at n=26A136981
• The initial prime in the first set of n consecutive primes for which p+4 is semiprime.at n=7A137625
• Primes congruent to 38 mod 59.at n=36A142765
• Primes congruent to 59 mod 61.at n=39A142857
• Primes p such that continued fraction of (1 + sqrt(p))/2 has period 11: primes in A146335.at n=30A146356
• Primes p such that p plus or minus the sum of the fourth powers of its digits is a prime in both cases.at n=27A179595
• First of a run of 4 or more consecutive primes which all equal 1 (mod 3).at n=40A185942
• Primes of the form 7n^3+5.at n=3A201254
• Primes of the form 2n^2 + 5.at n=30A201474
• Primes of the form 8n^2 + 5.at n=15A201612
• Primes of the form 5n^2 - 7.at n=13A201788
• Primes p such that b=2*p+1 is semiprime, c=2*b+1 is 3-almost prime and d=2*c+1 is 4-almost prime.at n=16A235646
• Primes p = x^2 + y^2 such that x - y is a cube greater than one.at n=24A282405
• Numbers n such that 13^n is the highest power of 13 dividing A240751(n).at n=11A286007
• Number of partitions p of n such that (number of numbers in p that have multiplicity 1) <= (number of numbers in p having multiplicity > 1).at n=40A330146
• G.f. A(x) satisfies A(x) = 1 / ((1 - 4 * x) * (1 - x * A(x)^2)).at n=5A349535