%I #13 Jan 11 2025 10:48:51
%S 23,47,104,128,185,207,266,290,347,371,423,452,509,533,590,614,671,
%T 695,752,776,833,857,914,936,995,1019,1076,1100,1152,1181,1238,1262,
%U 1319,1343,1400,1424,1481,1505,1562,1586,1643,1665
%N Numbers k such that 2 and 5 occur juxtaposed in the base-9 representation of k but not of k-1.
%t SequencePosition[Table[If[SequenceCount[IntegerDigits[n,9],{2,5}]>0||SequenceCount[IntegerDigits[n,9],{5,2}]>0,1,0],{n,2000}],{0,1}][[;;,2]] (* _Harvey P. Dale_, Jan 11 2025 *)
%Y Cf. A007095.
%K nonn,base
%O 1,1
%A _Clark Kimberling_