30301

Appears in sequences

• Expansion of 1/((1-2x)(1-3x)(1-6x)(1-9x)).at n=4A025939
• Composite numbers which in base 6 contain their largest proper factor as a substring.at n=12A063156
• Duplicate of A063156.at n=12A063876
• a(n) = ceiling((9*(9/4)^n - 4) / 5).at n=12A108870
• a(n) = 3*10^(2*n) + 3*10^n + 1.at n=2A177019
• Semiprimes formed by concatenating n, n, and 1 for n = 1, 2, 3,....at n=12A210711
• T(n,k) is the k-th partition of n in graded reverse lexicographic ordering (A080577) encoded as concatenation of parts which are represented in (zeroless) bijective base-9 numeration (A052382) and separated by zeros; triangle T(n,k), n >= 0, 1 <= k <= A000041(n), read by rows.at n=37A332567