18960

Appears in sequences

• a(n) = Sum_{j=1..n} j*prime(j).at n=24A014285
• Triangle read by rows: T(0,0) = 1, T(n,k) = Sum_{j=max(0,1-k)..n-k} (2^j)*(binomial(k+j,1+j) + binomial(k+j+1,1+j))*T(n-1,k-1+j).at n=11A085734
• T(n, k) = [x^k] (2*n)! [z^(2*n)] 1/cos(z)^x, triangle read by rows, for 0 <= k <= n.at n=17A088874
• Triangle read by rows: T(n,k) is the number of down-up permutations on [n] with k left-to-right maxima.at n=26A098906
• G.f.: cube root of theta series of E_6 lattice (cf. A004007).at n=3A109143
• Numbers k such that there is a bigger number m satisfying A000203(k) = A000203(m) = m + k - gcd(m,k).at n=35A124140
• Triangle read by rows: T(n,k) is the number of partitions of the set {1,2,...,n}, having exactly k blocks consisting of entries of the same parity (0<=k<=n).at n=56A124424
• Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1111-1111 pattern in any orientation.at n=11A146940
• a(n) = 512n + 16.at n=36A157475
• Number of nX6 binary arrays without the pattern 0 0 1 diagonally, antidiagonally or horizontally.at n=2A189261
• T(n,k)=Number of nXk binary arrays without the pattern 0 0 1 diagonally, antidiagonally or horizontally.at n=30A189264
• Number of 3Xn binary arrays without the pattern 0 0 1 diagonally, antidiagonally or horizontally.at n=5A189265
• Ordered differences of numbers 3^j-2^j, as in A001047.at n=32A205105
• The number of reversible primes (palindromic or emirps) by increasing permissible leading digit and by length.at n=24A220344
• Indices of the start of 10 successive distinct digits in the decimal expansion of Pi.at n=9A258157
• Numbers equal to the sum of three oblong numbers in arithmetic progression.at n=41A292314
• Number of Sós permutations of {0,1,...,n}.at n=38A330503
• a(n) is the number of partitions of n in which no part is divisible by 3 minus the number of basis partitions of n.at n=53A350636
• Numbers k such that A226199(k) = 7^k + k is prime.at n=3A370657
• Composite numbers with properties that its digits (which may appear with multiplicity) may not appear in any of its factors (wherein the digits may also appear with multiplicity) and the combined digits of the product and the factors must have at least one of each of the ten digits.at n=31A370972