cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Previous Showing 11-18 of 18 results.

A044824 Positive integers having distinct base-13 run lengths.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 28, 42, 56, 70, 84, 98, 112, 126, 140, 154, 168, 169, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 197, 211, 225, 239, 253, 267, 281, 295, 309, 323, 337, 338, 352, 364, 365, 366, 367, 368, 369, 370, 371
Offset: 1

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Author

Keywords

Examples

			338 = 200_13 is in the sequence as it has distinct run lengths of distinct digits (2, 1). - _David A. Corneth_, Jan 04 2021
		

Crossrefs

Programs

  • Mathematica
    Select[Range[400],Union[Tally[Length/@Split[IntegerDigits[#,13]]][[All,2]]] == {1}&] (* Harvey P. Dale, Sep 15 2020 *)

A044825 Positive integers having distinct base-14 run lengths.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165, 180, 195, 196, 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 226, 241, 256, 271, 286, 301, 316, 331, 346, 361, 376, 391, 392, 407, 420, 421, 422, 423
Offset: 1

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Author

Keywords

Examples

			346 = 1AA_14 is in the sequence as it has distinct run lengths of distinct digits (1, 2). - _David A. Corneth_, Jan 04 2021
		

Crossrefs

A044826 Positive integers having distinct base-15 run lengths.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 225, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254, 257, 273, 289, 305, 321, 337, 353, 369, 385, 401, 417, 433, 449, 450, 466
Offset: 1

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Author

Keywords

Examples

			337 = 177_15 is in the sequence as it has distinct run lengths of distinct digits (1, 2). - _David A. Corneth_, Jan 04 2021
		

Crossrefs

A044827 Positive integers having distinct base-16 run lengths.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 34, 51, 68, 85, 102, 119, 136, 153, 170, 187, 204, 221, 238, 255, 256, 272, 273, 274, 275, 276, 277, 278, 279, 280, 281, 282, 283, 284, 285, 286, 287, 290, 307, 324, 341, 358, 375, 392, 409, 426, 443, 460, 477
Offset: 1

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Author

Keywords

Examples

			324 = 144_16 is in the sequence as it has distinct run lengths of distinct digits (1, 2). - _David A. Corneth_, Jan 04 2021
		

Crossrefs

A297148 Numbers whose base-10 digits d(m), d(m-1),..., d(0) have m=0 or else d(i) = d(i+1) for some i in {0,1,...,m-1}.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 100, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 122, 133, 144, 155, 166, 177, 188, 199, 200, 211, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 233, 244, 255, 266, 277, 288, 299, 300
Offset: 1

Views

Author

Clark Kimberling, Jan 15 2018

Keywords

Comments

These numbers comprise the complement of the set of numbers in the union of A297146 and A297147.
Differs from A044821 first for 1001, which is in this sequence but not in A044821. - R. J. Mathar, Jan 17 2018

Examples

			Base-10 digits of 65536: 6,5,5,3,6, so that 65536 is in the sequence.
		

Crossrefs

Programs

  • Maple
    read("transforms") :
    isA297148 := proc(n)
        local dgs,ud;
        dgs := convert(n,base,10) ;
        if nops(dgs) < 2 then
            return true;
        end if;
        if 0 in DIFF(dgs) then
            true;
        else
            false;
        end if;
    end proc:
    for n from 1 to 300 do
        if isA297148(n) then
            printf("%d,",n) ;
        end if;
    end do: # R. J. Mathar, Jan 18 2018
  • Mathematica
    a[n_, b_] := Sign[Differences[IntegerDigits[n, b]]]; z = 300;
    b = 10; t = Table[a[n, b], {n, 1, 10*z}];
    u = Select[Range[z], ! MemberQ[t[[#]], 0] && First[t[[#]]] == 1 &]   (* A297146 *)
    v = Select[Range[z], ! MemberQ[t[[#]], 0] && First[t[[#]]] == -1 &]  (* A297147 *)
    Complement[Range[z], Union[u, v]]  (* A297148 *)

A048321 Reading a(n) expansion from left to right, run lengths strictly decrease.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 440, 441, 442, 443, 444, 445, 446, 447, 448
Offset: 1

Views

Author

Patrick De Geest, Feb 15 1999

Keywords

Crossrefs

Programs

  • Haskell
    import Data.List (group)
    a048321 n = a048321_list !! (n-1)
    a048321_list = filter f [0..] where
       f x = all (< 0) $ zipWith (-) (tail zs) zs
             where zs =  map length $ group $ show x
    -- Reinhard Zumkeller, May 01 2015

A048307 Numbers whose decimal expansions, read from left to right, have run lengths that strictly increase.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 100, 111, 122, 133, 144, 155, 166, 177, 188, 199, 200, 211, 222, 233, 244, 255, 266, 277, 288, 299, 300, 311, 322, 333, 344, 355, 366, 377, 388, 399, 400, 411, 422, 433, 444, 455, 466, 477, 488
Offset: 0

Views

Author

Patrick De Geest, Feb 15 1999

Keywords

Crossrefs

A380596 Numbers with embedded palindromes as proper substrings of the term.

Original entry on oeis.org

100, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 122, 133, 144, 155, 166, 177, 188, 199, 200, 211, 220, 221, 222, 223, 224, 225, 226, 227, 228, 229, 233, 244, 255, 266, 277, 288, 299, 300, 311, 322, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 344, 355, 366, 377, 388, 399
Offset: 1

Views

Author

James S. DeArmon, Jan 27 2025

Keywords

Comments

An embedded palindrome is a substring of at least two contiguous digits (since a single digit is trivially a palindrome). E.g., 121 is a palindrome, but has no embedded palindromes; 110 has the embedded palindrome "11".
Alternatively, k contains a proper substring of the form dd or ded, where d and e are single decimal digits (i.e., a length-2 or -3 palindrome). - Michael S. Branicky, Feb 08 2025

Examples

			100 is a term, since "00" is a palindrome; 1001 is a term for the same reason.
1020 is a term, since "020" is a palindrome; 10201 is a term for the same reason.
		

Crossrefs

Cf. A002113.
Significant overlap with A044821 for terms below 1000.

Programs

  • Python
    from itertools import combinations
    def get_all_substrings(string):
        length = len(string) + 1
        return [string[x:y] for x, y in combinations(range(length), r=2)]
    def is_palindrome(n):
        return str(n) == str(n)[::-1]
    def ok(n):
        subsets = get_all_substrings(str(n))
        subsets = [subset for subset in subsets if is_palindrome(subset) and len(subset)>1 and len(subset)0
    print([k for k in range (100,400) if ok(k)])
    
  • Python
    def ok(n):
        s = str(n)
        return any(p == p[::-1] and len(p) < len(s) for p in (s[i:i+j] for j in (2, 3) for i in range(len(s)-j+1)))
    print([k for k in range(400) if ok(k)]) # Michael S. Branicky, Feb 08 2025
Previous Showing 11-18 of 18 results.