24456

Appears in sequences

• a(1) = 1, a(n) = Sum_{k=1..n} (k mod 3) * a(n-k) for n >= 2.at n=14A141685
• a(n) = p(n)*p(n+2)-p(n+1), where p(n) is the n-th prime.at n=35A152530
• 3-comma numbers: n occurs in the sequence S[k+1]=S[k]+10*last_digit(S[k-1])+first_digit(S[k]) for three different splittings n=concat(S[0],S[1]).at n=29A166513
• Let S(1)={1} and, for n>1 let S(n) be the smallest set containing x+1, x+2, and 2*x for each element x in S(n-1). a(n) is the number of elements in S(n).at n=19A168043
• a(1)=a(2)=a(3)=1, a(4)=3; thereafter a(n) = a(n-1) + a(n-3).at n=27A179070
• a(n) = 54*n^2 - 78*n + 36.at n=22A277983
• Triangle read by rows: T(0,0) = 1; T(n,k) = T(n-1, k) + 2*T(n-1, k-1) + 3*T(n-1, k-2) + 4*T(n-1, k-3) + 5*T(n-1, k-4) + 6*T(n-1, k-5) for k = 0..5*n; T(n,k)=0 for n or k < 0.at n=47A319092
• Number of ways to write n as an ordered sum of 6 primes (counting 1 as a prime).at n=45A341985
• 2nd row of the 3-Zeckendorf array (A136189), including prepended terms.at n=28A372760
• Numbers k such that sigma(k) = psi(k) + phi(k) + tau(k)^3.at n=0A390578