2601899

Properties

Appears in sequences

• a(n) = 2*a(n-1) + a(n-2) - a(n-3) for n >= 3, starting with a(0) = 1, a(1) = 3, and a(2) = 6.at n=18A006356
• 3-wave sequence starting with 1, 1, 1.at n=38A038196
• Bottom line of 3-wave sequence A038196, also bisection of A006356.at n=9A038223
• Expansion of (1-x)/(1-2*x-x^2+x^3).at n=19A077998
• Expansion of x*(1-x)/(1-2*x-x^2+x^3).at n=20A106803
• First row sum of the matrix M^n, where M is the 3 X 3 matrix [[6, 5, 3], [5, 4, 2], [3, 2, 1]] (n>=0).at n=6A122187
• 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=42A187068
• 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=40A187070
• a(n) is the number of symmetrical linear hydrocarbon chains with n C-C bonds.at n=35A370377
• Expansion of x + 1/(-x - 1/(-x - 1/(-x + 1))).at n=18A373567
• Prime numbersat n=190002