39865

Appears in sequences

• Narayana's cows sequence: a(0) = a(1) = a(2) = 1; thereafter a(n) = a(n-1) + a(n-3).at n=29A000930
• Octagonal pyramidal numbers: a(n) = n*(n+1)*(2*n-1)/2.at n=33A002414
• Strong pseudoprimes to base 86.at n=14A020312
• Pisot sequence P(4,6).at n=24A048625
• Pisot sequence P(6,9).at n=23A048626
• Expansion of (1-x)^3/(1 - 4*x + 3*x^2 - x^3).at n=10A052529
• Number of ways to tile a 2 X n room with 1 X 2 Tatami mats. At most 3 Tatami mats may meet at a point.at n=28A068921
• a(n) = a(n-1) + a(n-3) for n >= 3, with a(0) = 1, a(1) = a(2) = 0. This recurrence can also be used to define a(n) for n < 0.at n=32A078012
• Expansion of (1 - x)/(1 + x - 2*x^2 + x^3).at n=14A078039
• Sarrus numbers with more than 2 distinct prime factors.at n=26A080747
• a(n) = Sum_{k=0..floor(n/3)} C(n-2k,k-1).at n=31A099560
• Pseudotwinprimes p+2 for primes p such that p+2 divides p^(p+2)+2 and p+2 is composite.at n=17A100873
• Devaraj numbers: squarefree r-prime-factor (r>1) integers N=p1*...*pr such that phi(N)=(p1-1)*...*(pr-1) divides gcd(p1-1,...,pr-1)^2*(N-1)^(r-2).at n=11A104016
• Devaraj numbers (A104016) which are not Carmichael numbers.at n=1A104017
• Pseudoprimes (base-2) equal to product of 4 primes not necessarily distinct.at n=3A112441
• a(n) = n-1, if n <= 2, otherwise A107458(n-1) + A107458(n-2).at n=34A135851
• a(0) = 0, a(1) = 1, a(2) = 2; for n > 2, a(n) = a(n-1) + 2*a(n-2) + a(n-3).at n=15A141015
• a(n) = Sum_{k=1..n} b(k)*a(n - k) for n >= 1, where b(n) = b(n-2) + b(n-3) for n >= 3 with b(0) = 0 and b(1) = b(2) = 1.at n=15A141683
• 1 followed by A141015.at n=16A142474
• Odd squarefree numbers n such that the cyclotomic polynomial Phi(n,x) is not coefficient convex.at n=18A146960