21897

Appears in sequences

• Numbers k such that k divides s(k), where s(1)=1, s(j)= s(j-1) + j*7^(j-1).at n=30A014948
• a(n) = diagonal sum of left justified array T given by A027113.at n=26A027131
• a(n) = (n - 1)*(n^2 + n - 1).at n=28A033445
• Number of partitions satisfying cn(0,5) + cn(1,5) <= cn(2,5) + cn(3,5) and cn(0,5) + cn(4,5) <= cn(2,5) + cn(3,5).at n=41A039886
• a(n) = n*a(n-1) + (1/2)*(1+(-1)^n), a(0)=0.at n=8A080227
• Number of ways to write prime(n) as sum of distinct divisors of prime(n)+1.at n=71A085496
• Place n points on each of the three sides of a triangle, 3n points in all; a(n) = number of nondegenerate triangles that can be constructed using these points (plus the 3 original vertices) as vertices.at n=16A130748
• Numerator of Euler(n, 1/28).at n=4A157206
• a(1)=3; for n > 1, a(n) = 1 + a(n-1) + gcd( a(n-1)*(a(n-1)+2), A073829(a(n-1)) ).at n=30A167053
• E.g.f.: Sum_{n>=0} (exp(3^n*x) - 1)^n/n!, an analog of the Bell numbers (A000110).at n=3A168408
• Number of (n+1) X (n+1) -3..3 symmetric matrices with every 2 X 2 subblock having sum zero and one or two distinct values.at n=17A211322
• Number of nonnegative integer arrays of length n+7 with new values 0 upwards introduced in order, no three adjacent elements all unequal, and containing the value 4.at n=6A211844
• T(n,k)=Number of nonnegative integer arrays of length n+2k+1 with new values 0 upwards introduced in order, no three adjacent elements all unequal, and containing the value k+1.at n=42A211849
• Number of nonnegative integer arrays of length 2n+8 with new values 0 upwards introduced in order, no three adjacent elements all unequal, and containing the value n+1.at n=2A211853
• Number of (n+1) X (2+1) 0..1 arrays with each row divisible by 3 and each column divisible by 5, read as a binary number with top and left being the most significant bits.at n=10A262466
• Irregular triangle read by rows: T(n,k) = number of unsigned unichromosonal genomes with n genes at 3-break distance k from a fixed genome, 0 <= k <= floor(n/2).at n=28A264614
• The number of initial values <= 10^n whose trajectory under the iteration x -> A306938(x) reaches 1.at n=8A306971
• a(n) = (4*n^3 + 30*n^2 + 50*n)/3 + 1.at n=23A323218