49024

Appears in sequences

• Expansion of e.g.f. exp(-2*x)/(1-x).at n=9A000023
• Expansion of (theta_3(z)*theta_3(11z) + theta_2(z)*theta_2(11z))^4.at n=28A028612
• Number of primitive (period n) periodic palindromic structures using a maximum of two different symbols.at n=32A056513
• Number of primitive (period n) periodic palindromic structures using exactly two different symbols.at n=31A056518
• Numbers m such that 2*m - sigma(m) is a divisor of m and greater than one, where sigma = A000203 is the sum of divisors.at n=18A060326
• Numbers n such that sigma(n) is congruent to n mod phi(n).at n=19A066679
• Solutions to k + 2*phi(k) = sigma(k) where phi is A000010 and sigma is A000203.at n=6A076373
• Triangle T(n,k), 0<=k<=n, read by rows, defined by: T(n,k)=0 if k>n, T(n,0) = A000108(n); T(n+1,k)= Sum_{j=0..n} T(n-j,k-1)*binomial(2j+1,j+1).at n=48A090285
• a(n) = (2^n)*a(n-1) + (2^(n-1))*a(n-2), a(0)=1, a(1)=2.at n=5A096658
• Numbers that appear in A076078.at n=27A097210
• a(n) = the number of sets of distinct positive integers with a least common multiple of A025487(n), i.e., A076078(A025487(n)).at n=27A097211
• Numbers m such that A076078(m) = m, where A076078(m) equals the number of sets of distinct positive integers with a least common multiple of m.at n=21A097214
• Numbers m such that A076078(m) = m and bigomega(m) >= 2; or in other words, A097214, excluding powers of 2.at n=5A097215
• Numbers n such that A076078(m)=n for some m, excluding powers of 2.at n=11A097416
• Numbers k > 0 such that k^2 is a centered pentagonal number (A005891).at n=6A129557
• Duplicate of A136488.at n=15A135098
• a(n) = 2^n - A005418(n).at n=15A136488
• Number of 6 X n binary arrays without the pattern 0 1 diagonally, vertically, antidiagonally or horizontally.at n=18A188557
• Number of (w,x,y,z) with all terms in {1,...,n} and w*x+y*z>n^2.at n=27A212136
• G.f.: Sum_{n>=0} x^n / ( (1+x)^(n+1) * (1 - 4*(n+1)*x) ).at n=6A245375