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A044389
Numbers n such that string 5,7 occurs in the base 10 representation of n but not of n-1.
0
57, 157, 257, 357, 457, 557, 570, 657, 757, 857, 957, 1057, 1157, 1257, 1357, 1457, 1557, 1570, 1657, 1757, 1857, 1957, 2057, 2157, 2257, 2357, 2457, 2557, 2570, 2657, 2757, 2857, 2957, 3057, 3157, 3257, 3357, 3457, 3557
OFFSET
1,1
MATHEMATICA
Transpose[SequencePosition[Table[If[SequenceCount[IntegerDigits[n], {5, 7}]>0, 1, 0], {n, 4000}], {0, 1}]][[2]] (* The program uses the SequencePosition and SequenceCount functions from Mathematica version 10 *) (* Harvey P. Dale, Jul 09 2015 *)
CROSSREFS
Sequence in context: A044689 A250606 A356423 * A044770 A008877 A338078
KEYWORD
nonn,base
STATUS
approved