19069

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 55.at n=0A031643
• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 98 ones.at n=15A031866
• Numbers k such that 27*2^k-1 is prime.at n=35A050539
• Initial term in sequence of four consecutive primes separated by 3 consecutive differences each <=6 (i.e., when d=2,4 or 6) and forming d-pattern=[4, 6, 2]; short d-string notation of pattern = [462].at n=28A078851
• Primes p such that the differences between the 5 consecutive primes starting with p are (4,6,2,6).at n=8A078955
• Primes p such that the sum of the digits of p is not prime, but the sum of each digit raised to the 4th power is prime.at n=12A091368
• Expansion of 1/((1-x)(1-x-x^2)(1-x-x^2-x^3)).at n=13A095681
• Primes congruent to 42 mod 53.at n=39A142572
• Primes congruent to 12 mod 59.at n=36A142739
• Primes congruent to 37 mod 61.at n=36A142835
• a(n) = n^3 - 3*(n+3)^2.at n=28A153260
• Primes which are the fourth element of a generalized Wieferich sequence.at n=9A179400
• Primes which are the fifth element of a generalized Wieferich sequence.at n=3A179678
• Numbers k such that log(A156668(k)*(1 + k mod 2))/k^2 is smaller than for any prior k.at n=25A186082
• Number of compositions [p(1), p(2), ..., p(k)] of n such that p(j) <= 2*p(j-1) and p(j-1) <= 2*p(j).at n=19A224957
• The Wiener index of the graph obtained by applying Mycielski's construction to a benzenoid consisting of a linear chain of n hexagons.at n=13A228597
• Number of (n+2)X(3+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000101 00010001 or 00010101.at n=6A260604
• Number of (n+2)X(7+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000101 00010001 or 00010101.at n=2A260608
• T(n,k)=Number of (n+2)X(k+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000101 00010001 or 00010101.at n=38A260609
• T(n,k)=Number of (n+2)X(k+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000101 00010001 or 00010101.at n=42A260609