A190896 Least positive integer whose binary representation does not occur in the concatenation of the binary representations of all earlier terms.

1, 2, 3, 4, 8, 10, 13, 15, 16, 19, 20, 32, 35, 37, 38, 40, 49, 54, 61, 64, 67, 68, 73, 74, 79, 80, 85, 87, 93, 103, 117, 121, 127, 128, 131, 134, 136, 139, 141, 143, 148, 151, 152, 155, 156, 158, 160, 165, 166, 170, 172, 174, 182, 193, 197, 217, 218, 239, 241, 251, 256, 259, 262, 264, 267, 268

Offset: 0

Author

M. F. Hasler, Dec 29 2012

Keywords

• easy
• nonn
• base

Comments

See the variant A118250 for comments and examples.

Crossrefs

Cf. A190897 (concatenation of binary representations), A118248 (the same with nonnegative integers), A118250, A118252 (variants where binary representations are reversed).

Programs

PARI

A190896(n,show=0,a=1)={my(c=[0],S=[],L); for(k=1,n, show && print1(a","); while( setsearch(S,binary(a++)),); c=concat(c,binary(a)); S=[]; for(i=0,#c-L=#binary(a), c[i+1] & for(j=i+L,min(i+L+1,#c), S=setunion(S,Set(t=[vecextract(c,2^j-2^i)])))));a}