18221

Appears in sequences

• a(n) = (6*n+1)*(6*n+5).at n=22A001513
• a(n) = (4*n+1)*(4*n+5).at n=33A003185
• Losing initial positions in game: two players alternate in removing >= 1 stones; last player wins; first player may not remove all stones; each move <= 3 times previous move.at n=29A003411
• Smallest losing position after your opponent has taken k stones in a variation of "Fibonacci Nim".at n=25A054736
• Squarefree n such that the elliptic curve n*y^2 = x^3 - x arising in the "congruent number" problem has rank 3.at n=30A062693
• Expansion of (1 - x + x^2)/(1 - x - x^4).at n=33A103632
• a(n)=the sum of the (1,2)- and (1,3)-entries and twice the (1,4)-entry of the matrix P^n + T^n, where the 4 X 4 matrices P and T are defined by P=[0,1,0,0;0,0,1,0;0,0,0,1;1,0,0,0] and T=[0,1,0,0;0,0,1,0;0,0,0,1;1,0,0,1].at n=32A109526
• Group the triangular numbers so that the n-th group sum is a multiple of n. 1, (3, 6, 10, 15), (21), (28), (36, 45, 55, 66, 78), (91, 105, 120, 136, 153, 171, 190), ... Sequence contains n-th group sum divided by n.at n=26A114032
• Second trisection of A061037.at n=44A142599
• a(n) = (8*n+5)*(8*n+9).at n=16A146302
• A functionally symmetric Polynomial as a triangle of coefficients: p(x,n)=If[n == 0, 1, (x + 1)^n + 2^(n - 4)*Sum[(2^m + 2*m + 2)*x^m*(1 + x^(n - 2*m)), {m, 1, n - 1}]].at n=57A146954
• a(n) = 100*n^2 + 100*n + 21.at n=13A152161
• a(n) = A061037(7*n+2).at n=19A165943
• Number of (n+1) X 7 binary arrays with every 2 X 2 subblock commuting with each of its horizontal and vertical 2 X 2 subblock neighbors.at n=11A186459
• a(n) = a(n-1) - a(n-2) if n is prime or a(n-1) + a(n-2) otherwise. a(1) = a(2) = 1.at n=34A192439
• Expansion of 1/(1 - x - x^2 + x^3 - x^4 + x^6).at n=30A193146
• Composite squarefree numbers n such that p(i)-3 divides n+3, where p(i) are the prime factors of n.at n=3A225703
• Number of (19,14)-reverse multiples with n digits.at n=72A226517
• a(n) = prime(n)^2 - 4*prime(n).at n=30A245034
• Row sums of A291940.at n=17A291942