-109

Appears in sequences

• a(1) = 0, a(2) = -2; for n > 2, a(n) + a(n-2) - a(n-3) - a(n-5) - ... - a(n-p) = (-1)^(n+1)*n if n is prime, otherwise = 0, where p = largest prime < n.at n=29A002120
• cos(arcsin(arctan(x)))=1-1/2!*x^2+5/4!*x^4-109/6!*x^6+4521/8!*x^8...at n=3A012091
• sech(arcsin(arcsinh(x)))=1-1/2!*x^2+5/4!*x^4-109/6!*x^6+4073/8!*x^8...at n=3A012122
• sech(arctan(arctanh(x)))=1-1/2!*x^2+5/4!*x^4-109/6!*x^6+2729/8!*x^8...at n=3A012239
• Carlitz-Riordan q-Catalan numbers (recurrence version) for q=-5.at n=3A015100
• a(n+1) = a(n) - n (if n is odd), a(n+1) = a(n) * n (if n is even).at n=7A047906
• Smallest (in magnitude) nonzero number m such that n!+m is prime.at n=57A053714
• McKay-Thompson series of class 18f for the Monster group.at n=66A058544
• Expansion of (1-x-x^N)/((1-x)(1-x^2)(1-x^3)...(1-x^N)) for N = 10.at n=33A060029
• a(n) = mu(n)*prime(n).at n=28A062007
• Determinant of the n X n matrix whose element (i,j) equals |i-j| (Mod 3).at n=37A071768
• First order recursion: a(0)=1; a(n) = sigma(1,n) - a(n-1).at n=25A083238
• Abundance values of numbers whose abundance is (+-1) times a prime.at n=12A088006
• A nonsense sequence.at n=81A089077
• Row sums of triangle A091698.at n=6A091699
• Lower triangular matrix T, read by rows, such that the row sums of T^n form the (2n)-dimensional partition numbers.at n=47A096652
• Sum_{k=1..n-1} J(2*n,k)*k^2, where J(i,j) is the Jacobi symbol.at n=22A097543
• First differences of A081145.at n=65A099004
• Coefficients of numerator polynomials of g.f.s for a certain necklace problem involving prime numbers.at n=24A103728
• Coefficients of numerator polynomials of g.f.s for a certain necklace problem involving prime numbers.at n=20A103728