A043216 Numbers k such that 0 and 1 occur juxtaposed in the base-10 representation of k but not of k-1.

10, 100, 201, 210, 301, 310, 401, 410, 501, 510, 601, 610, 701, 710, 801, 810, 901, 910, 1000, 1201, 1210, 1301, 1310, 1401, 1410, 1501, 1510, 1601, 1610, 1701, 1710, 1801, 1810, 1901, 1910, 2001, 2010, 2100, 2201, 2210, 2301

Offset

1,1

Links

Table of n, a(n) for n=1..41.

Prog

(Python)
def ok(n):
    sn, snm1 = str(n), str(n-1)
    return ("01" in sn or "10" in sn) and not ("01" in snm1 or "10" in snm1)
print(list(filter(ok, range(1, 2302)))) # Michael S. Branicky, Aug 23 2021

Crossrefs

Sequence in context: A072082 A078259 A101655 * A044342 A119052 A029774

Adjacent sequences: A043213 A043214 A043215 * A043217 A043218 A043219

Keyword

nonn,base

Author

Clark Kimberling

Status

approved