Numbers n such that string 6,1 occurs in the base 10 representation of n but not of n-1.

Terms

a(0) =61a(1) =161a(2) =261a(3) =361a(4) =461a(5) =561a(6) =610a(7) =661a(8) =761a(9) =861a(10) =961a(11) =1061a(12) =1161a(13) =1261a(14) =1361a(15) =1461a(16) =1561a(17) =1610a(18) =1661a(19) =1761a(20) =1861a(21) =1961a(22) =2061a(23) =2161a(24) =2261a(25) =2361a(26) =2461a(27) =2561a(28) =2610a(29) =2661