Numbers n such that string 5,6 occurs in the base 9 representation of n but not of n+1.

Terms

a(0) =51a(1) =132a(2) =213a(3) =294a(4) =375a(5) =456a(6) =467a(7) =537a(8) =618a(9) =699a(10) =780a(11) =861a(12) =942a(13) =1023a(14) =1104a(15) =1185a(16) =1196a(17) =1266a(18) =1347a(19) =1428a(20) =1509a(21) =1590a(22) =1671a(23) =1752a(24) =1833a(25) =1914a(26) =1925a(27) =1995a(28) =2076a(29) =2157