30589

Appears in sequences

• G.f.: -1 + Product_{k>=1} (1 + prime(k)*x^prime(k)).at n=38A002099
• Expansion of x/(1 - 5*x - 4*x^2).at n=7A015537
• Strong pseudoprimes to base 19.at n=21A020245
• Numbers whose base-4 representation contains exactly four 1's and four 3's.at n=21A045133
• Numbers k such that the sum of the k-th triangular number and (k+2)-nd triangular number is a triangular number.at n=11A076049
• a(n) = sigma_4(n^2)/sigma_2(n^2).at n=13A084218
• a(0)=1, a(1)=1, a(n) = 13*a(n/2) for n=2,4,6,..., a(n) = 12*a((n-1)/2) + a((n+1)/2) for n=3,5,7,....at n=20A116524
• Smallest integer m > 1 such that m!^(m + n) divides (m^2)!.at n=11A244443
• Number of tilings of a 14 X n rectangle using 2n heptominoes of shape I.at n=23A250664
• Numbers whose base-b expansions, for both b=3 and b=4, include no digits other than 1 and b-1.at n=18A262958
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 249", based on the 5-celled von Neumann neighborhood.at n=33A271014
• a(n) is the least term that is not a power of p, the n-th prime, in the sequence of numbers whose consecutive divisors have a ratio satisfying numerator - denominator = p-1.at n=5A280964
• a(n) = Sum_{j=1..n} Sum_{k=1..n} phi(2*j*k) / phi(k).at n=35A372664