19540

Appears in sequences

• a(n) = a(n-1) + a(n-2) + 1, with a(0) = 1 and a(1) = 10.at n=17A022324
• Riordan array (1/sqrt(1-2*x-3*x^2), 1/sqrt(1-2*x-3*x^2) -1).at n=47A116392
• Least n such that nextprime(p*n) > p*nextprime(n) where p runs through the prime numbers (if p is prime then nextprime(p)=p).at n=24A117102
• Number of partitions of n having exactly one part with multiplicity 3.at n=43A118808
• G.f.: A(x) = INV(x - x*INV(x - x^2*INV(x - x^3*INV(x - x^4*INV(x - ...))))), where INV(F(x)) = series reversion of F(x).at n=9A194956
• Number of nX3 0..3 arrays with every element neighboring horizontally or vertically both a 0 and a 1, and 2 introduced before 3 in row major order.at n=5A204296
• Number of nX6 0..3 arrays with every element neighboring horizontally or vertically both a 0 and a 1, and 2 introduced before 3 in row major order.at n=2A204299
• T(n,k)=Number of nXk 0..3 arrays with every element neighboring horizontally or vertically both a 0 and a 1, and 2 introduced before 3 in row major order.at n=30A204301
• T(n,k)=Number of nXk 0..3 arrays with every element neighboring horizontally or vertically both a 0 and a 1, and 2 introduced before 3 in row major order.at n=33A204301
• Number of (w,x,y) with all terms in {0,...,n} and w>floor((x+y)/3).at n=30A212974
• Number of (n+2)X(2+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 3 5 6 or 8 and every 3X3 diagonal and antidiagonal sum not equal to 0 3 5 6 or 8.at n=4A252328
• Number of (n+2)X(5+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 3 5 6 or 8 and every 3X3 diagonal and antidiagonal sum not equal to 0 3 5 6 or 8.at n=1A252331
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 3 5 6 or 8 and every 3X3 diagonal and antidiagonal sum not equal to 0 3 5 6 or 8.at n=16A252334
• T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum equal to 0 3 5 6 or 8 and every 3X3 diagonal and antidiagonal sum not equal to 0 3 5 6 or 8.at n=19A252334
• 27-gonal numbers: a(n) = n*(25*n-23)/2.at n=40A255186
• a(n) = Sum_{k=0..n} p(k) where the p(k) are the partial sums of row n of A365676.at n=22A365675
• a(n) = A068346(A276086(n)), where A068346 is the second arithmetic derivative, and A276086 is the primorial base exp-function.at n=52A370131