100047

Appears in sequences

• Suppose you take the ten digits 0..9, arrange them in any order and then either concatenate adjacent ones or separate them with a plus or minus sign, e.g., 98-76+5-4-32+10 or 9-8-765+3041-2. The first expression totals to "1", the second example totals to "2275". This sequence lists the positive integers that cannot be expressed in this way.at n=17A108224
• Number of n X 6 binary arrays with each 1 adjacent to exactly one 1 vertically and one 1 horizontally.at n=10A183338
• a(n) = Sum_{k=1..n} sigma(k)*sigma(2*k), where sigma(n) = A000203(n) is the sum of the divisors of n.at n=34A347108