Exponent of least power of 2 having exactly n consecutive 7's in its decimal representation.

A131541

Exponent of least power of 2 having exactly n consecutive 7's in its decimal representation.

Terms

    a(0) =0a(1) =15a(2) =27a(3) =24a(4) =181a(5) =317a(6) =2309a(7) =972a(8) =25264a(9) =131979a(10) =279275a(11) =279269a(12) =1727605a(13) =6030752a(14) =8760853a(15) =77235364

External references