123904

Appears in sequences

• Expansion of (1 + 2*x)/(1 - 2*x)^3.at n=10A014477
• a(n) = (10*n + 2)^2.at n=35A017294
• a(n) = (11*n)^2.at n=32A017390
• a(n) = (12*n + 4)^2.at n=29A017570
• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (F(2), F(3), ...), t = A000201 (lower Wythoff sequence).at n=31A024593
• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (F(2), F(3), F(4), ...), t = A000201 (lower Wythoff sequence).at n=30A025107
• Numbers whose prime factors are 2 and 11.at n=31A033848
• An intermediate sequence for counting nonisomorphic circulant directed p^2-graphs, indexed by odd primes p.at n=4A038780
• A convolution triangle of numbers generalizing Pascal's triangle A007318.at n=48A049325
• Lesser of a primitive pair such that n and its 10's complement are simultaneously square.at n=3A068075
• Squares whose digits can be arranged in increasing cyclic order - to form a substring of 123456789012345678901234567890...at n=12A068708
• Numbers n such that n and its 10's complement are both squares, i.e., n and 10^k - n (where k is the number of digits in n) are squares.at n=16A068810
• Triangle T(n,k) (n >= 2, 1 <= k <= n-1) giving number of non-crossing trees with n nodes and height k.at n=51A072248
• Perfect powers (index > 1) whose digits can be arranged in ascending order or as a substring of 123456789012345678901234567890123...at n=15A076966
• Smaller of the two successive squares which differ in the use of only one digit.at n=33A078187
• Triangular numbers + 1 squared.at n=26A086601
• Smallest number beginning with 1 and having exactly n divisors.at n=32A089707
• Numerators of the average length of a line segment picked at random in the unit n-ball for odd n.at n=5A093530
• Numbers k such that A094471(k) is prime.at n=33A096847
• Numbers of the form (4^i)*(11^j), with i, j >= 0.at n=27A107988