384199200

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=12A001108
• Expansion of 1/((1 - x)*(1 - 2*x - x^2)).at n=22A048739
• Numbers k such that k and k+1 are powerful numbers.at n=10A060355
• Powerful numbers of the form k^2 - 1.at n=8A060859
• Expansion of g.f. x/(1 - x - 3*x^2 - x^3).at n=24A097076
• a(n) = 2*A079291(n) (twice squares of Pell numbers).at n=12A114619
• Consider all Pythagorean triples (X,X+1,Z) ordered by increasing Z; sequence gives Z-(X+1) values.at n=11A115598
• X-values of solutions to the equation X*(X + 1) - 8*Y^2 = 0.at n=6A132592
• a(n) = -sin^2 (2*n*arccos n) = - sin^2 (2*n*arcsin n).at n=3A173194
• Least number k such that k-th triangular number is the sum of two nonzero squares in exactly n ways.at n=12A274686
• Numbers k such that k and k+1 are both antiharmonic numbers (A020487).at n=20A335389
• Smaller of a pair of numbers (m, m+1) such that both are products P of composite prime powers with omega(P) > 1.at n=6A358174
• Expansion of e.g.f. 1/(1 - x - x^2)^(x^3).at n=11A371158
• The smaller of a pair of successive powerful numbers without a nonsquarefree number between them.at n=27A371190