a(n) is the smallest nonnegative integer such that a(n)! contains a string of exactly n consecutive 4's.

A254449

a(n) is the smallest nonnegative integer such that a(n)! contains a string of exactly n consecutive 4's.

Terms

    a(0) =0a(1) =4a(2) =21a(3) =63a(4) =117a(5) =375a(6) =1325a(7) =1253a(8) =5741a(9) =30455a(10) =83393a(11) =68094a(12) =565882a(13) =2666148a(14) =1514639

External references