183922

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=17A006054
• 3-wave sequence starting with 1, 1, 1.at n=31A038196
• Expansion of g.f.: 1/(1 - 2*x - x^2 + x^3).at n=15A106805
• Expansion of ( 1-x^3+x^4+x^5-x^8 ) / ( 1-2*x^3-x^6+x^9 ).at n=49A120771
• Semiprimes in A006054.at n=1A122500
• a(1)=1, a(2)=2, a(n)=a(n-1)+floor(a(n-2)*a(n-1)/(a(n-2)+a(n-1))).at n=36A173090
• 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=35A187068
• 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=34A187069
• 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=33A187070
• Maximal term of TRIP-Stern sequence of level n corresponding to permutation triple (e,13,e).at n=29A271485
• a(n) is the number of symmetrical linear hydrocarbon chains with n C-C bonds.at n=30A370377