137903

Appears in sequences

• a(n) = 6*a(n-1) - a(n-2) + 2 with a(0) = 0, a(1) = 3.at n=7A001652
• Related to Pythagorean triples: alternate terms of A001652 and A046090.at n=7A046727
• Expansion of 1/((1 - x)*(1 - 2*x - x^2)).at n=13A048739
• Number of 14 X n binary arrays with path of adjacent 1's from upper right corner to lower left corner.at n=1A069336
• Pell oblongs.at n=7A084159
• Duplicate of A048739.at n=13A090757
• Expansion of g.f. (1-x-x^2)/(1-x-3*x^2-x^3).at n=15A097075
• Pythagorean triples of nearly isosceles triangle.at n=18A114336
• Row sums of A181657.at n=26A181658
• Numbers k where d/k reaches a new record, with d the distance from the k-th triangular number to the nearest square.at n=18A229117
• Rectangular array read upwards by columns: T = T(n,k) = number of paths from (0,1) to (n,k), where 0 <= k <= 2, consisting of segments given by the vectors (1,1), (1,0), (1,-1).at n=47A247311
• Pairs of integers (a,b) such a^2 + (a+1)^2 = b^2.at n=14A261116
• Numbers k with property that there is an m = m(k) such that m(m+1)/2 divides k(k+1)/2 and m(k) > m(i) for all i < k.at n=31A309423
• Semiprimes that are (perimeter^2 - hypotenuse^2) of a Pythagorean triple.at n=10A389589