261120

Appears in sequences

• Theta series of 32-dimensional Quebbemann lattice Q_32.at n=3A002272
• E.g.f.: exp(tan(x)-tanh(x))=1+4/3!*x^3+160/6!*x^6+544/7!*x^7+17920/9!*x^9...at n=10A013451
• Expansion of e.g.f. sec(tan(x) - tanh(x)) (even-indexed coefficients only).at n=5A013455
• Theta series of 14-dimensional integral laminated lattice LAMBDA14.3 with minimal norm 4.at n=5A047626
• Numbers k such that usigma(phi(k)) is a prime.at n=39A065875
• Smallest k such that d(phi(k)) - phi(d(k)) = -n, where d(k) = A000005(k) and phi(k) = A000010(k).at n=22A078151
• Numbers k such that phi(k) is a perfect 8th power.at n=28A078168
• Nonsquarefree numbers m such that rad(m+1)=rad(m)+1, where rad(m)=A007947(m) is the squarefree kernel of m.at n=5A081084
• Numbers m such that A007947(m) = A007947(k) and A007947(m+1) = A007947(k+1), for some k < m.at n=8A087914
• Triangle read by rows: nonzero coefficients of polynomials 2^n*E(n,x), with E the Euler polynomials.at n=39A099932
• a(n) = sigma() [A000203] applied n times to prime(n).at n=9A101303
• a(n) = 4a(n-1) - 6a(n-2) + 4a(n-3), n > 3; a(0) = 3, a(1) = 2, a(2) = a(3) = 0.at n=18A133209
• Weight distribution of [256,63,64] extended binary primitive BCH (or XBCH) code.at n=33A151660
• 11th column of A172119.at n=18A172320
• a(n) = sinh(2*arccosh(n))^2 = 4*n^2*(n^2 - 1).at n=16A173121
• Monotonic ordering of nonnegative differences 8^i-4^j, for 40>= i>=0, j>=0.at n=28A192168
• Number of bitstrings of length n (with at least two runs) where the last two runs have different lengths.at n=17A208901
• Total area of all squares and rectangles after 2^n stages in the toothpick structure of A139250, assuming the toothpicks have length 2.at n=9A211012
• Number of binary words of length n which have no 0^b 1 1 0^a 1 0 1 0^b - matches, where a=b=2.at n=18A234592
• Number of non-palindromic n-tuples of 4 distinct elements.at n=8A242026