19603

Properties

Appears in sequences

• Take solution to Pellian equation x^2 - n*y^2 = 1 with smallest positive y and x >= 0; sequence gives a(n) = x, or 1 if n is a square. A002349 gives values of y.at n=57A002350
• Lower prime of a record difference between it and the second prime after it.at n=15A031133
• Smallest positive integer x satisfying the Pell equation x^2 - D*y^2 = 1 for nonsquare D and positive y.at n=50A033313
• Numerators of continued fraction convergents to sqrt(58).at n=13A041100
• Numerators of continued fraction convergents to sqrt(232).at n=5A041432
• Numerators of continued fraction convergents to sqrt(522).at n=9A041998
• Primes of the form k^2 + 3.at n=23A049423
• Prime lucky numbers k (from A031157) such that nextprime(k)=nextlucky(k).at n=25A057698
• Smallest prime that begins with the n-th square in decimal notation.at n=13A065145
• Numbers n such that the number formed by the digits of 2n sorted in descending order is equal to the sum of the divisors of n after the digits of each divisor have been sorted in descending order (all zeros dropped).at n=5A083389
• Primes of the form 2*n^2+1.at n=18A090698
• Least integer x>0 such that x^2=ceiling(x*r*floor(x/r)) where r=sqrt(n).at n=57A091015
• Larger prime in pair prime(k) +/- k for some k.at n=28A107637
• Number of 7-almost primes 7ap such that 2^n < 7ap <= 2^(n+1).at n=19A120038
• Duplicate of A049423.at n=23A121825
• a(n) is the n-th prime of the form n*x^2+1.at n=17A128970
• Primes congruent to 15 mod 59.at n=36A142742
• Primes congruent to 22 mod 61.at n=37A142820
• Let N(p,i) denote the result of applying "nextprime" i times to p; a(n) = smallest prime p such that N(p,2) - p = 2*n, or -1 if no such prime exists.at n=28A144103
• a(n) = 57122*n^2 - 47320*n + 9801.at n=0A156721