18018

Appears in sequences

• Coefficients of Legendre polynomials.at n=5A001801
• Smaller of unitary amicable pair.at n=2A002952
• Triangle of coefficients of Legendre polynomials P_n (x).at n=27A008316
• Perimeters of more than one primitive Pythagorean triangle.at n=30A024408
• a(n) = (1/(9n-3))*M(3n; n,n,n), where M() is a multinomial coefficient.at n=4A024489
• Distinct numbers in the triangle of denominators in Leibniz's Harmonic Triangle.at n=51A046202
• Distinct even numbers in the triangle of denominators in Leibniz's Harmonic Triangle.at n=41A046204
• Numbers to the right of the central elements in the triangle of denominators in Leibniz's Harmonic Triangle.at n=43A046207
• Partial sums of A051836.at n=10A051923
• Truncated triangular pyramid numbers: a(n) = Sum_{k=4..n} (k*(k+1)/2 - 9).at n=43A051937
• Triangular array of Motzkin polynomial coefficients.at n=53A055151
• Triangle (0 <= k <= n) read by rows: T(n, k) is the number of Schröder paths from (0,0) to (2n,0) having k peaks.at n=50A060693
• a(n) = n*(n-1)*(n-3)*(n-5).at n=14A062765
• Unitary amicable numbers.at n=4A063991
• Composite numbers k such that the difference between the odd and even aliquot parts of k divides k.at n=21A066193
• Difference between larger and smaller terms of n-th amicable pair.at n=11A066539
• Integers n such that n = A067030(j) for some j and A067286(j) < A067034(j).at n=19A068798
• Numbers n for which there is a unique k such that n = k + reverse(k).at n=43A072427
• Number of increasing rooted trees where each node at height h has 0 or h+1 children.at n=14A075534
• Denominator of Sum_{i+j+k=n, i,j,k>=1} (i*j)/k.at n=15A076175