22548

Appears in sequences

• One half of the number of permutations of [n] such that the differences have 4 runs with the same signs.at n=4A000486
• Number of monosubstituted alkanes C(n)H(2n+1)-X of the form shown in the Comments lines that are not stereoisomers.at n=22A000624
• Triangle T(n,k) = P(n,k)/2, n >= 2, 1 <= k < n, of one-half of number of permutations of 1..n such that the differences have k runs with the same signs.at n=31A008970
• Coordination sequence for MgNi2, Position Ni1.at n=37A009933
• Sum of first prime(n) primes.at n=24A022094
• Self-convolution of array T given by A026637.at n=8A026966
• 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 100.at n=34A031598
• Numbers having four 3's in base 9.at n=29A043468
• "Ceiling of hypotenuses": a(n) = ceiling(sqrt(a(n-1)^2 + a(n-2)^2)), a(1)=1, a(2)=3.at n=37A104805
• Sum of primes < 2^n.at n=8A130739
• Terms of A007504 divisible by 3.at n=30A249679
• Numbers k such that k^8192 + (k+1)^8192 is prime.at n=6A274237
• Expansion of 1/(1 - x*Product_{k>=1} 1/(1 - k*x^k)).at n=11A299162
• Triangle read by rows: T(n,k) is the number of 4-ary strings of length n with k indispensable digits, with 0 <= k <= n.at n=40A330509
• Number of nodes in graph BC(n,2) when the internal nodes are counted with multiplicity.at n=15A343994
• Numbers that are the sum of eight fourth powers in exactly nine ways.at n=23A345841
• The sum S of the maximum number of consecutive primes starting with 2 such that S <= prime(n)^2.at n=35A346134
• Number of integer partitions of n containing all of their own nonzero first differences.at n=46A364674
• a(n) = Sum_{k=1..n} sigma_2( (n/gcd(k,n))^2 ).at n=7A372996