34934
domain: N
Appears in sequences
- a(1)=1, a(n) is the smallest integer > a(n-1) such that the sum of elements of the simple continued fraction for S(n)=1/a(1)+1/a(2)+...+1/a(n) equals n*(n+1)/2 the n-th triangular number.at n=33A071184
- Triangle read by rows: T(n,k) is the number of skew Dyck paths of semilength n having k UU's starting at level 0 (i.e., doublerises at level 1; n >= 0, 0 <= k <= floor(n/2)).at n=39A129168
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, -1), (0, -1, 1), (0, 1, 0), (1, 1, -1)}.at n=11A148137
- Semiprimes that are the sum of 10 consecutive primes.at n=40A185347
- Number of (n+2) X (2+2) 0..3 arrays with every 3 X 3 subblock row and column sum 3 or 6 and every diagonal and antidiagonal sum not 3 or 6.at n=3A251773
- Number of (n+2)X(4+2) 0..3 arrays with every 3X3 subblock row and column sum 3 or 6 and every diagonal and antidiagonal sum not 3 or 6.at n=1A251775
- T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum 3 or 6 and every diagonal and antidiagonal sum not 3 or 6.at n=11A251779
- T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum 3 or 6 and every diagonal and antidiagonal sum not 3 or 6.at n=13A251779
- a(1) = 1; a(n+1) = Sum_{k=1..n} lcm(a(k),a(n))/a(n).at n=29A287006
- a(n) = a(n-1) + 3*a(n-2) -2*a(n-3) - 2*a(n-4), where a(0) = -2, a(1) = 0, a(2) = 0, a(3) = 1.at n=20A295858
- Number of primes less than 10^n with digits in nonincreasing order.at n=13A345326