19219

Properties

Appears in sequences

• Numbers k such that 15*2^k + 1 is prime.at n=30A002258
• Fibonacci sequence beginning 4, 17.at n=16A022134
• a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n+1-k), where k = floor((n+1)/2), s = A023531, t = (Lucas numbers).at n=20A024319
• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = A023531, t = (Lucas numbers).at n=19A024882
• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 88 ones.at n=23A031856
• Primes p such that the decimal digits of p^2 can be partitioned into two or more nonzero squares.at n=36A048646
• Smallest prime > 2n+1 beginning and ending with 2n+1, or 0 if no such prime exists.at n=9A070278
• Smallest prime p with at least two non-overlapping occurrences of n in decimal representation of p.at n=18A103611
• Primes p = prime(i) of level (1,3), i.e., such that A118534(i) = prime(i-3).at n=31A118467
• Smallest prime of the form k*prime(n+1)+prime(n) = j*prime(n+2)+prime(n+1) for free integer multipliers k and j.at n=12A129918
• Numbers k such that k and k^2 use only the digits 1, 2, 3, 6 and 9.at n=27A136981
• Second smallest m such that (2^n)! + m is a prime.at n=10A138346
• Primes congruent to 44 mod 59.at n=36A142771
• Primes congruent to 4 mod 61.at n=39A142802
• Primes of the form XYX, where Y is a single digit.at n=24A154270
• a(n) = 961*n - 1.at n=19A158412
• a(n) = 20*n^2 - 1.at n=30A158491
• Number of nX2 1..5 arrays containing at least one of each value, all equal values connected, rows considered as a single number in nondecreasing order, and columns considered as a single number in decreasing order.at n=6A166839
• Emirps with a single 2 as the only prime digit.at n=29A179033
• 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=28A179595