1900080
domain: N
Appears in sequences
- E.g.f.: (1-x)^2/(1-3*x+x^2).at n=7A052567
- Numbers that can be expressed as the difference of the squares of primes in exactly fifteen distinct ways.at n=23A092011
- Location of records in A099564.at n=28A099565
- Numbers k such that k | A002129(k).at n=7A348583
- For n > 1, if n appears in the sequence then a(n) = lastindex(n), where lastindex(n) is the index of the last appearance of n. Otherwise a(n+1) = a(n)/(n+1) if (n+1)|a(n), otherwise a(n)*(n+1), a(1) = 1 and a(2) = 1*2.at n=29A362332
- G.f. satisfies A(x) = 1 + x^3*A(x)^4*(1 + x*A(x)).at n=23A365725
- Triangle read by rows: T(n,k) = Sum_{j=0..k} (-1)^(k-j) * binomial(k,j) * (4+j)^n.at n=41A391633