The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A043248 Numbers k such that 4 and 7 occur juxtaposed in the base-10 representation of k but not of k-1. 0
 47, 74, 147, 174, 247, 274, 347, 374, 447, 470, 547, 574, 647, 674, 740, 774, 847, 874, 947, 974, 1047, 1074, 1147, 1174, 1247, 1274, 1347, 1374, 1447, 1470, 1547, 1574, 1647, 1674, 1740, 1774, 1847, 1874, 1947, 1974, 2047 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..41. MATHEMATICA SequencePosition[Table[If[SequenceCount[IntegerDigits[n], {4, 7}]>0 || SequenceCount[ IntegerDigits[n], {7, 4}]>0, 1, 0], {n, 2100}], {0, 1}][[All, 2]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 20 2019 *) CROSSREFS Sequence in context: A338273 A165335 A039425 * A044028 A126095 A132259 Adjacent sequences: A043245 A043246 A043247 * A043249 A043250 A043251 KEYWORD nonn,base AUTHOR Clark Kimberling STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 19 16:10 EDT 2024. Contains 376013 sequences. (Running on oeis4.)