488281250

Appears in sequences

• Expansion of (1-3*x)/(1-5*x).at n=13A020699
• Pisot sequences E(2,10), L(2,10), P(2,10), T(2,10).at n=12A020729
• a(n) = 5*a(n-2), starting 1,2.at n=25A026383
• a(n) = 5*a(n-2), starting 1,2,4.at n=25A026395
• Numbers n such that n-th Pisano number = 6*n.at n=12A095687
• Bhaskara twins: n such that 2*n^2 = X^3 and 2*n^3 = Y^2.at n=24A106318
• a(n) is the number of shapes of balanced trees with constant branching factor 5 and n nodes. The node is balanced if the size, measured in nodes, of each pair of its children differ by at most one node.at n=37A131891
• a(3*n) = 3*a(3*n-1)-3*a(3*n-2)+2*a(3*n-3), a(3*n+1) = 3*a(3*n)-3*a(3*n-1)+2*a(3*n-2), a(3*n+2) = 3*a(3*n+1)-3*a(3*n) with a(0)=1, a(1)=2, a(2)=3.at n=37A133335
• a(n) = 5*a(n-2) for n > 2; a(1) = 2, a(2) = 5.at n=24A162963
• Number of tilings of a fortress (or Penta-Aztec-Diamond) of order n.at n=7A232997
• Numbers k such that the k-th cyclotomic polynomial has a root mod 5.at n=37A245478
• Least number k such that k^3 is the sum of two nonzero squares in exactly n ways.at n=18A273238
• a(n) is the smallest nonnegative integer k where exactly n ordered pairs of positive integers (x, y) exist such that x^2 + y^2 = k.at n=13A328151
• Numbers which contain the "Look and Say" description (cf. A045918) of all their prime factors, counted with multiplicity.at n=9A367974