42421
domain: N
Appears in sequences
- Slowest increasing sequence beginning with 1 whose digits satisfy the rule d*2.at n=12A102252
- a(n) = number of n-digit terms in A058369.at n=6A147523
- Semiprimes formed by concatenating n, n, and 1 for n = 1, 2, 3,....at n=18A210711
- Sum_{i=1..n} Sum_{j=1..n} (i OR j), where OR is the binary logical OR operator.at n=37A258438
- a(n) = a(n-1) + a(n-3), with a(0) = 1, a(1) = 4, a(2) = 8.at n=25A385633
- a(n) = A005117(A390138(n) + 1).at n=21A390241