login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A043998
Numbers k such that 0 and 3 occur juxtaposed in the base-10 representation of k but not of k+1.
1
30, 103, 130, 203, 230, 309, 330, 403, 430, 503, 530, 603, 630, 703, 730, 803, 830, 903, 930, 1003, 1039, 1103, 1130, 1203, 1230, 1309, 1330, 1403, 1430, 1503, 1530, 1603, 1630, 1703, 1730, 1803, 1830, 1903, 1930, 2003, 2039
OFFSET
1,1
LINKS
MATHEMATICA
With[{j = 0, k = 3}, Position[Partition[Array[Boole[Total@ {SequenceCount[#, {j, k}], SequenceCount[#, {k, j}]} > 0] &@ IntegerDigits[#] &, 2100], 2, 1], {1, 0}][[All, 1]]] (* Michael De Vlieger, Aug 27 2021 *)
SequencePosition[Table[If[SequenceCount[IntegerDigits[n], {0, 3}]>0||SequenceCount[ IntegerDigits[ n], {3, 0}]>0, 1, 0], {n, 2100}], {1, 0}][[All, 1]] (* Harvey P. Dale, Jun 11 2022 *)
CROSSREFS
Sequence in context: A280911 A043218 A039395 * A101056 A316362 A081370
KEYWORD
nonn,base
STATUS
approved