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

 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 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A296908 Numbers n whose base-60 digits d(m), d(m-1), ..., d(0) have #(pits) < #(peaks); see Comments. 4
 3720, 3721, 3780, 3781, 3782, 3840, 3841, 3842, 3843, 3900, 3901, 3902, 3903, 3904, 3960, 3961, 3962, 3963, 3964, 3965, 4020, 4021, 4022, 4023, 4024, 4025, 4026, 4080, 4081, 4082, 4083, 4084, 4085, 4086, 4087, 4140, 4141, 4142, 4143, 4144, 4145, 4146, 4147 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS A pit is an index i such that d(i-1) > d(i) < d(i+1); a peak is an index i such that d(i-1) < d(i) > d(i+1). The sequences A296906..A296908 partition the natural numbers. We have a(n) = A000027(n) for n=1..3600, but not for n = 3601. See the guides at A296712 and A296882. LINKS Clark Kimberling, Table of n, a(n) for n = 1..10000 EXAMPLE The base-60 digits of 13395721 are 1,2,1,2,1; here #(pits) = 1 and #(peaks) = 2, so that 13395721 is in the sequence. MATHEMATICA z = 200; b = 60; d[n_] := Differences[Sign[Differences[IntegerDigits[n, b]]]]; Select[Range [z], Count[d[#], -2] == Count[d[#], 2] &] (* A296906 *) Select[Range [z], Count[d[#], -2] < Count[d[#], 2] &] (* A296907 *) Select[Range [z], Count[d[#], -2] > Count[d[#], 2] &] (* A296908 *) CROSSREFS Cf. A296882, A296712, A296906, A296907. Sequence in context: A180396 A158917 A252421 * A237736 A289512 A260860 Adjacent sequences: A296905 A296906 A296907 * A296909 A296910 A296911 KEYWORD nonn,base,easy AUTHOR Clark Kimberling, Jan 12 2018 STATUS approved

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

Last modified December 2 07:06 EST 2022. Contains 358493 sequences. (Running on oeis4.)