21760

Appears in sequences

• Expansion of 1/((1+x)*(1-x)^5).at n=29A001752
• Number of totally symmetric plane partitions that fit in an n X n X n box.at n=7A005157
• Number of Barlow packings with group R3(bar)m(O) that repeat after 6n layers.at n=14A011955
• exp(arctanh(x) + arctan(x)) = 1 + 2*x + 4/2!*x^2 + 8/3!*x^3 + 16/4!*x^4 + 80/5!*x^5 +...at n=8A013174
• cos(arctanh(x)+arctan(x))=1-4/2!*x^2+16/4!*x^4-640/6!*x^6+21760/8!*x^8...at n=4A013179
• Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 73.at n=39A031571
• Numbers k whose decimal representation, read as a base-17 value and divided by k, yields an integer.at n=14A032565
• Penrice Christmas gift numbers, Card-matching numbers (Dinner-Diner matching numbers): Triangle T(n,k) = number of ways to get k matches for a deck with n cards, 2 of each kind.at n=28A059056
• Card-matching numbers (Dinner-Diner matching numbers).at n=10A059070
• Numbers with exactly 2 odd integers in their Collatz (or 3x+1) trajectory.at n=44A062052
• Solutions to phi(gpf(x)) - gpf(phi(x)) = 14 = c are special multiples of 17, x = 17k, where greatest prime factors of factor k were observed from {2, 3, 5}, i.e., it is smaller than 17. See solutions to other even cases of c (=A070813): A007283 for 0, A070004 for 2, A070815 for 254, A070816 for 65534. Gpf = greatest prime factor.at n=35A070814
• Binomial transform of A073145: a(n)=Sum(binomial(n,k)*A073145(k),(k=0,..,n)).at n=23A075115
• a(n) = A000695(A014486(n)).at n=22A083931
• Moebius transform of Jacobsthal numbers.at n=16A104723
• Triangle, read by rows, of Stirling numbers of first kind, S1(n,k), multiplied by k^k, for n >= 1, 1<=k<=n.at n=18A105196
• a(n) = n^2*(n^2 - 1)/3.at n=16A112742
• a(n) = Sum_{k=floor((n+1)/2)..n} J(k+1), J(k) = A001045(k).at n=14A129362
• First differences of the binomial transform of the distinct partition numbers (A000009).at n=13A129519
• Numerator of the expected number of random moves in Tower of Hanoi problem with n disks starting on peg 1 and ending on peg 3.at n=4A134939
• Consider numbers m,n such that UnitaryPhi(m)=UnitaryPhi(n)=3*(m*n)^(1/2)/4, m <= n; sequence gives values of n.at n=5A143649