18756

Appears in sequences

• a(n) = floor(Fibonacci(n)/4).at n=25A004697
• Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite EUO = EU-1 Nan[AlnSi112-nO224] starting with a T1 atom.at n=13A019127
• Numbers k such that k^2 is palindromic in base 5.at n=21A029988
• Sums of 4 distinct powers of 5.at n=25A038476
• a(n) = (Fibonacci(6*n+1) - 1)/4.at n=4A049661
• Number of permutations satisfying -k <= p(i) - i <= r and p(i) - i not in I, i=1..n, with k=1, r=5, I={1,3}.at n=22A079962
• (n+1)^2*a(n+1) = (17n^2+17n+6)*a(n) - 72*n^2*a(n-1).at n=5A093388
• a(n+3) = 3*a(n+2) + 5*a(n+1) + a(n), a(0) = 0, a(1) = 1, a(2) = 3.at n=8A110526
• Numbers n such that F(2*n - 1) is prime, where F(m) is a Fibonacci number.at n=29A117595
• a(n) = a(n-1) + a(n-2) + 1 if n is a multiple of 6, otherwise a(n) = a(n-1) + a(n-2).at n=21A131132
• Number of unsigned permutations of size n whose "cycle graph" (or "breakpoint graph") is composed of alternating cycles of length at most 3.at n=8A132803
• Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 01000-11111-01000 pattern in any orientation.at n=18A147023
• Number of 2-sided strip polypons with n cells.at n=32A151533
• a(n) = 729*n - 198.at n=25A156772
• Numbers n with property that n+41, n^2+41 and n^3+41 are all primes.at n=12A175260
• a(n) = sum of all divisors of all positive integers <= prime(n).at n=35A244583
• Numbers k such that 5*10^k + 81 is prime.at n=21A291611
• a(n) is the integer k that minimizes |k/Fibonacci(n) - 1/4|.at n=25A293553
• a(n) appears in the congruences modulo 4 or 32 of Markoff numbers m(n) = A002559(n) for odd or even m(n).at n=29A309376
• Approximation of the 2-adic integer arctan(4) up to 2^n.at n=15A309756