28431

Appears in sequences

• Numbers k that divide s(k), where s(1)=1, s(j)=13*s(j-1)+j.at n=33A014861
• a(n) = (2*n - 15)*n^2.at n=27A015247
• Numbers k that divide 7^k + 2^k.at n=40A045580
• Numbers k that divide 7^k + 5^k.at n=31A045596
• Odd numbers divisible by exactly 8 primes (counted with multiplicity).at n=6A046321
• Numbers n such that n | 9^n + 8^n + 7^n + 6^n + 5^n + 4^n.at n=32A057260
• Next-to-middle coefficient in expansion of Product_{k=1..n} (1 + x^k).at n=20A068202
• Partial sums of n 3-spaced triangular numbers beginning with t(3), e.g., a(2) = t(3)+t(6) = 6+21 = 27.at n=25A085788
• a(n) is the smallest positive integer k such that, if kn is written in base 2, it requires exactly n ones.at n=16A102032
• Numbers of the form (3^i)*(13^j).at n=25A107364
• Number of solutions to +- 1 +- 2 +- .. +- n = 3.at n=21A113037
• a(n) = 3^n*tribonacci(n) or (3^n)*A001644(n+1).at n=5A127215
• Sequence is identical to its third differences in absolute value: a(0), a(1), a(2), a(2n+1)=3a(2n)-3a(2n-1)+2a(2n-2), a(2n+2)=3a(2n+1)-3a(2n), with a(0)=a(1)=0, a(2)=1.at n=33A131665
• Smallest odd n-almost prime m such that m-2 and m+2 are both prime (cousin primes).at n=7A145031
• a(n) = (n/4)*3^(n/2)*((1+sqrt(3))^2+(-1)^n*(1-sqrt(3))^2).at n=13A187273
• a(n) = 3*a(n-1) - 6*a(n-2), with a(0)=0, a(1)=1.at n=14A190960
• Array: row n shows the coefficients of the characteristic polynomial of the n-th principal submatrix of f(i,j)=min(3i-2,3j-2) (A204028).at n=37A204029
• Number of triples (w,x,y) with all terms in {0,...,n} and |w-x| + |x-y| <= w+x+y.at n=30A213481
• a(n) = 13*3^n.at n=7A258597
• a(n) = 3^n*Fibonacci(n).at n=7A261397