A044236 Numbers k such that string 6,1 occurs in the base 8 representation of k but not of k-1.

49, 113, 177, 241, 305, 369, 392, 433, 497, 561, 625, 689, 753, 817, 881, 904, 945, 1009, 1073, 1137, 1201, 1265, 1329, 1393, 1416, 1457, 1521, 1585, 1649, 1713, 1777, 1841, 1905, 1928, 1969, 2033, 2097, 2161, 2225, 2289, 2353

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base
• changed

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A007094.

Programs

Mathematica

A044236Q[k_] := StringContainsQ[IntegerString[k, 8], "61"] && StringFreeQ[IntegerString[k - 1, 8], "61"];
Select[Range[5000], A044236Q] (* Paolo Xausa, Sep 03 2025 *)