18698

Appears in sequences

• a(n) = floor(n*phi^19), where phi is the golden ratio, A001622.at n=2A004934
• a(n) = round(n*phi^19), where phi is the golden ratio, A001622.at n=2A004954
• Numbers k such that the continued fraction for sqrt(k) has period 53.at n=25A020392
• Fibonacci sequence beginning 2, 6.at n=18A022112
• Smallest m such that A065623(m) = n.at n=13A065624
• Numbers k such that sigma(sigma(k) - k) = phi(sigma(k) + k).at n=15A074886
• Indices of prime tribonacci numbers, minus 1.at n=9A092835
• Number of partitions of n into 3-smooth parts.at n=49A105420
• a(n) = gcd(Lucas(n)+1, Fibonacci(n)-1).at n=36A115314
• Half-indexed Lucas numbers second version L(n)=A000032=Lucas numbers a(0)=2, a(1)=2, a(2)=1, a(3)=2, a(4)=3, a(5)=3, a(2n)=L(n), for n>2: a(2n+1)=L(n)+L(n-3)=2*L(n-1) for n>5: a(n)+a(n+2)=a(n+4) a(2n)=L(n), so a(n)=L(n/2).at n=41A127218
• Number of binary strings of length n with no substrings equal to 0000, 0001 or 1001.at n=19A164413
• a(n) = Sum_{k=1..n} k*C(n,k), where C(n,k) = number of binary sequences of length n and curling number k (A216955).at n=12A217941
• Expansion of 2*(x+1)*(x^4+6*x^3+5*x^2+6*x+1)/(x^6-18*x^3+1).at n=9A247035
• Numbers that are equal to the sum of the number of divisors of their first k arithmetic derivatives, for some k.at n=33A269459
• Solution of the complementary equation a(n) = 2*a(n-1) - a(n-2) + b(n-1) + n, where a(0) = 1, a(1) = 2, b(0) = 3, and (a(n)) and (b(n)) are increasing complementary sequences.at n=36A294872
• Triangle read by rows: T(n,k) is the number of n-digit numbers having a k-digit greatest prime factor.at n=14A294952
• One of the two successive approximations up to 13^n for 13-adic integer sqrt(3). Here the 4 (mod 13) case (except for n = 0).at n=4A322085
• Positive numbers k such that -k, -(k + 1), and -(k + 2) are 3 consecutive negative negaFibonacci-Niven numbers (A331088).at n=43A331090
• a(n) is the start of the first run of exactly n consecutive numbers not of the form x^2 + x*y + y^2.at n=22A357020