81853

Properties

Appears in sequences

• a(n) = 2*a(n-1) + a(n-2) - a(n-3), with a(0) = a(1) = 0, a(2) = 1.at n=16A006054
• 3-wave sequence starting with 1, 1, 1.at n=29A038196
• a(n) = prime((a(n-1)+1)/2), a(1) = 9.at n=12A104296
• Expansion of g.f.: 1/(1 - 2*x - x^2 + x^3).at n=14A106805
• Expansion of ( 1-x^3+x^4+x^5-x^8 ) / ( 1-2*x^3-x^6+x^9 ).at n=46A120771
• Triangle of 4-Eulerian numbers.at n=38A144698
• Let i be in {1,2,3}, let r >= 0 be an integer and n=2*r+i-1. Then a(n)=a(2*r+i-1) gives the quantity of H_(7,1,0) tiles in a subdivided H_(7,i,r) tile after linear scaling by the factor x^r, where x=sqrt((2*cos(Pi/7))^2-1).at n=33A187068
• Let i be in {1,2,3}, let r >= 0 be an integer and n=2*r+i-1. Then a(n)=a(2*r+i-1) gives the quantity of H_(7,2,0) tiles in a subdivided H_(7,i,r) tile after linear scaling by the factor x^r, where x=sqrt((2*cos(Pi/7))^2-1).at n=32A187069
• Let i be in {1,2,3}, let r >= 0 be an integer and n=2*r+i-1. Then a(n)=a(2*r+i-1) gives the quantity of H_(7,3,0) tiles in a subdivided H_(7,i,r) tile after linear scaling by the factor x^r, where x=sqrt((2*cos(Pi/7))^2-1).at n=31A187070
• a(n) = PrimePi(4^n) - PrimePi(2^n).at n=10A248957
• Maximal term of TRIP-Stern sequence of level n corresponding to permutation triple (e,13,e).at n=27A271485
• a(n) is the number of symmetrical linear hydrocarbon chains with n C-C bonds.at n=28A370377
• The number of digits in max(a,b,c), where a, b, and c are the smallest positive integer solutions to a/(b+c) + b/(a+c) + c/(a+b) = A283564(n).at n=8A371846
• a(n) = number of primes between n^2 and n^4.at n=32A380332
• Prime numbersat n=8004