1940449
domain: N
Appears in sequences
- a(n)-th triangular number is a square: a(n+1) = 6*a(n) - a(n-1) + 2, with a(0) = 0, a(1) = 1.at n=9A001108
- Squares of NSW numbers (A002315): x^2 such that x^2 - 2y^2 = -1 for some y.at n=4A008843
- Expansion of 1/((1 - x)*(1 - 2*x - x^2)).at n=16A048739
- Number of 17 X n binary arrays with path of adjacent 1's from upper right corner to lower left corner.at n=1A069339
- Repeatedly multiply (1,0,0) by ([1,2,2],[2,1,2],[2,2,3]); sequence gives leading entry.at n=9A090390
- Expansion of g.f. x/(1 - x - 3*x^2 - x^3).at n=18A097076
- a(n) = 2*a(n-1) + 2*a(n-3) + a(n-4), a(0) = 1, a(1) = 4, a(2) = 9, a(3) = 20.at n=16A111587
- Consider all Pythagorean triples (X,X+1,Z) ordered by increasing Z; sequence gives Z-(X+1) values.at n=8A115598
- Numbers n, satisfying A055231(n+1) - A055231(n) = 1, and with n and n+1 not squarefree.at n=13A140394
- Row sums of A181657.at n=32A181658
- Numbers k such that the distance between the k-th triangular number and the nearest square is at most 1.at n=32A229083
- Numbers k such that core(k+1) = core(k)+1 and k is not squarefree, where core(k) = A007913(k).at n=22A260198
- Numbers k such that k and k+1 are both antiharmonic numbers (A020487).at n=11A335389
- Positions of records in A375970.at n=18A375971