105704

Appears in sequences

• Triangle arising from (4,2) tennis ball problem, read by rows.at n=45A078990
• Integers n such that 2*11^n-1 is prime.at n=7A120378
• Number of Colombian variant Langford pairings (solutions to Langford problem such that exactly one instance of {1, 2, 3, ..., n-2, n} occurs between the two instances of n-1), up to reversal of the order.at n=18A336747