a(n) is the first composite number having the same base-(2n) digits as its prime factors (with multiplicity), excluding zero digits (or 0 if no such composite number exists).
A281189
a(n) is the first composite number having the same base-(2n) digits as its prime factors (with multiplicity), excluding zero digits (or 0 if no such composite number exists).
Terms
- a(0) =15a(1) =85a(2) =57a(3) =85a(4) =1111a(5) =185a(6) =4119a(7) =4369a(8) =489a(9) =451a(10) =13315a(11) =679a(12) =26533a(13) =985a(14) =1057a(15) =1285a(16) =179503a(17) =1387a(18) =82311a(19) =2005a(20) =2649a(21) =2047a(22) =4663957a(23) =2509a(24) =2761a(25) =3385a(26) =3097a(27) =3277a(28) =243895a(29) =4207
External references
- oeis: A281189