18889
domain: N
Appears in sequences
- Multilevel sieve: at k-th step, accept k numbers, reject k, accept k, ...at n=11A005209
- Pseudoprimes to base 60.at n=34A020188
- Strong pseudoprimes to base 60.at n=13A020286
- Nonzero numerators in asymptotic expansion of the Riemann-Seigel Z-function.at n=17A050276
- McKay-Thompson series of class 18b for the Monster group.at n=20A058537
- Triangle T(n,k) read by rows giving number of underdiagonal lattice paths from (0,0) to (n,k) using only steps R = (1,0), V = (0,1) and D = (3,1).at n=62A071946
- Triangle in A071946 with rows reversed.at n=58A108076
- Number of binary strings of length n with no substrings equal to 0000 0101 or 1011.at n=14A164435
- a(n) = 12*n^2 - 8*n + 9.at n=39A167585
- Numbers n such that 4n+1 is a palindromic prime.at n=38A192261
- Numbers n such that the trinomial x^n-x-1 is irreducible over GF(3).at n=33A223938
- Numbers whose septenary, octal and nonary representations are prime when read in decimal.at n=20A281252
- a(n) is the smallest k such that the sum of the number of divisors of the n numbers from k to k+n-1 equals tau(k+n).at n=10A348837