25346

Appears in sequences

• The n-th n-gonal number: a(n) = n*(n^2 - 3*n + 4)/2.at n=38A060354
• a(0)=1; a(1)=2; a(2)=5; a(3)=14; for n>3: a(n) = 8*a(n-1)-20*a(n-2)+16*a(n-3)-a(n-4).at n=9A126566
• Expansion of -2*x^2*(-3-2*x+x^2-x^3-2*x^4+x^5) / ( (1+x)^2*(x-1)^4 ).at n=37A178465
• Numbers n whose sum of anti-divisors is a permutation of their digits.at n=38A258786
• Number of independent sets of permutations of n points, i.e., subsets of the symmetric group of degree n, with the property that none of the elements in the subset can be generated by the rest of the subset.at n=4A263802
• 38-gonal numbers: a(n) = n*(18*n-17).at n=38A282850
• Integers m of the form m = 3*p + 5*q = 5*r + 7*s where {p,q} and {r,s} are pairs of consecutive primes.at n=10A283392
• G.f.: 1/(1 + x/(1 + x^3/(1 + x^6/(1 + x^10/(1 + x^15/(1 + ... + x^(k*(k+1)/2)/(1 + ...))))))), a continued fraction.at n=30A285484
• Numbers k such that k and k+1 are the product of exactly four distinct primes.at n=25A318896
• Numbers k such that sigma(k) = sigma(k+19), where sigma(k) is the sum of the divisors of k.at n=15A321533