21868

Appears in sequences

• a(0) = 1, a(n) = 26*n^2 + 2 for n>0.at n=29A010016
• Derivative of log of A002126.at n=48A023901
• a()=A037260 and its first [ A037261 ], 2nd [ A037262 ] and 3rd [ A037263 ] differences together include every number at most once and are monotonic and minimal.at n=22A037260
• Numerators of continued fraction convergents to sqrt(780).at n=5A042504
• Row 3 of A007754.at n=26A058794
• a(n) = 28a(n-1) - a(n-2), starting with a(0) = 2 and a(1) = 28.at n=3A090249
• a(n) = n^3 - 3*n.at n=28A121670
• Ulam's spiral (NNW spoke).at n=37A143860
• Numbers m where m^2 divides A159553(m), where A159553(m) = Sum_{k=0..m} binomial(m,k) * gcd(m,k).at n=15A159555
• Number of partitions p of n such that 2*(number of even numbers in p) <= (number of odd numbers in p).at n=44A241652
• Sum of the k-th arithmetic derivative of n-k for k=0..n.at n=19A258652
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 542", based on the 5-celled von Neumann neighborhood.at n=39A272811
• Union_{odd primes p, n >= 3} {T_p(n)}, where T_m(x) = x*T_{m-1}(x) - T_{m-2}(x), m >= 2, T_0(x) = 2, T_1(x) = x (dilated Chebyshev polynomials of the first kind).at n=28A299071
• Least nonnegative integer which requires n letters to spell in Turkish excluding spaces and hyphens.at n=28A305100
• Integers k equal to the sum over A024816(t) mod t, for some steps, starting with t = k and then using the result to feed the next calculation.at n=26A377002