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.

Showing 1-8 of 8 results.

A066960 Duplicate of A061827.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 7, 5, 4, 4, 3, 3, 3, 3, 1, 11, 1, 4, 7, 3, 5, 2, 4, 2, 1, 11, 6, 1, 3
Offset: 1

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Author

Keywords

A119999 Number of partitions of n into parts that occur in decimal representation as substrings of n.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 8, 6, 5, 5, 4, 4, 4, 4, 2, 12, 2, 5, 8, 4, 6, 3, 5, 3, 2, 12, 7, 2, 4, 4, 8, 3, 3, 6, 2, 12, 12, 5, 2, 4, 5, 3, 8, 3, 2, 12, 7, 5, 4, 2, 3, 3, 3, 3, 2, 12, 12, 12, 7, 4, 2, 3, 4, 5, 2, 12, 7, 5, 4, 4, 3, 2, 3, 3, 2, 12, 12, 5, 12, 4, 5, 3, 2, 3, 2, 12, 7, 12, 4, 4, 7, 3
Offset: 0

Views

Author

Reinhard Zumkeller, Jun 13 2006

Keywords

Comments

A120002 = first differences; A120003 = partial sums;
see A120000 and A120001 for records and where they occur: A120000(n)=a(A120001(n)).

Examples

			a(98) = #{98, 10*9+8, 2*9+10*8} = 3;
a(99) = #{99, 11*9} = 2;
a(100) = #{100, 10*10, 9*10+10*1, 8*10+20*1, 7*10+30*1, 6*10+40*1, 5*10+50*1, 4*10+60*1, 3*10+70*1, 2*10+80*1, 10+90*1, 100*1} = 12;
a(101) = #{101, 10*10+1, 9*10+11*1, 8*10+21*1, 7*10+31*1, 6*10+41*1, 5*10+51*1, 4*10+61*1, 3*10+71*1, 2*10+81*1, 10+91*1, 101*1} = 12;
a(102) = #{102, 10*10+2, 10*10+2*1, 9*10+6*2, ...} = 298.
		

Crossrefs

Programs

  • Haskell
    import Data.List (isInfixOf)
    a119999 n = p (filter ((`isInfixOf` show n) . show) [1..n]) n where
       p _  0 = 1
       p [] _ = 0
       p ks'@(k:ks) m | m < k     = 0
                      | otherwise = p ks' (m - k) + p ks m
    -- Reinhard Zumkeller, Aug 14 2011

A125289 Numbers with unique nonzero digit in decimal representation.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 20, 22, 30, 33, 40, 44, 50, 55, 60, 66, 70, 77, 80, 88, 90, 99, 100, 101, 110, 111, 200, 202, 220, 222, 300, 303, 330, 333, 400, 404, 440, 444, 500, 505, 550, 555, 600, 606, 660, 666, 700, 707, 770, 777, 800, 808, 880, 888, 900, 909
Offset: 1

Views

Author

Reinhard Zumkeller, Nov 26 2006

Keywords

Comments

A043537(a(n)) <= 2.
A043537(A004719(a(n))) = 1: A004719(a(n)) is a repdigit number, see A010785;
also numbers having exactly one partition into digit values of their decimal representations: A061827(a(n))=1.

Crossrefs

Cf. A125292.

Programs

  • PARI
    is(n, base=10) = #Set(select(sign, digits(n, base)))==1 \\ Rémy Sigrist, Mar 28 2020
    
  • PARI
    a(n,base=10) = { for (w=0, oo, if (n<=(base-1)*2^w, my (d=1+(n-1)\2^w, k=2^w+(n-1)%(2^w)); return (d*fromdigits(binary(k), base)), n -= (base-1)*2^w)) } \\ Rémy Sigrist, Mar 28 2020
  • Python
    A125289_list = [n for n in range(10**4) if len(set(str(n))-{'0'})==1]
    # Chai Wah Wu, Jan 04 2015
    
  • Python
    from itertools import count, product, islice
    def A125289_gen(): # generator of terms
        yield from (int(d+''.join(m)) for l in count(0) for d in '123456789' for m in product('0'+d,repeat=l))
    A125289_list = list(islice(A125289_gen(),20)) # Chai Wah Wu, Mar 14 2025
    

A125291 Number of partitions of n into positive digit values of its ternary representation.

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 4, 1, 1, 1, 6, 1, 1, 8, 8, 9, 9, 1, 10, 1, 11, 12, 12, 1, 13, 1, 1, 1, 15, 1, 1, 17, 17, 18, 18, 1, 1, 20, 1, 1, 21, 22, 22, 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, 1, 28, 1, 29, 30, 30, 1, 31, 1, 32, 33, 33, 34, 34, 35, 35, 36, 36, 1, 37, 1, 38, 39, 39, 1, 40, 1, 1, 1, 42
Offset: 1

Views

Author

Reinhard Zumkeller, Nov 26 2006

Keywords

Comments

a(A125292(n))=1; a(A125293(n))=floor((n+2)/2)=A008619(n).

Crossrefs

Formula

a(n) = 1 + floor(n/2) * (1 - 0^(A062756(n)*A081603(n))).

A125290 Numbers with at least two distinct digits in decimal representation, none of which is 0.

Original entry on oeis.org

12, 13, 14, 15, 16, 17, 18, 19, 21, 23, 24, 25, 26, 27, 28, 29, 31, 32, 34, 35, 36, 37, 38, 39, 41, 42, 43, 45, 46, 47, 48, 49, 51, 52, 53, 54, 56, 57, 58, 59, 61, 62, 63, 64, 65, 67, 68, 69, 71, 72, 73, 74, 75, 76, 78, 79, 81, 82, 83, 84, 85, 86, 87, 89, 91, 92, 93, 94, 95, 96, 97, 98, 112, 113, 114, 115, 116, 117, 118, 119, 121, 122, 123
Offset: 1

Views

Author

Reinhard Zumkeller, Nov 26 2006

Keywords

Comments

Also numbers having at least two partitions into digit values of their decimal representations: A061827(a(n)) > 1.
First differs from A101594 at a(83) = 123 != 131 = A101594(83). - Michael S. Branicky, Dec 13 2021

Crossrefs

Subsequence of A052382. Supersequence of A101594.

Programs

  • Haskell
    a125290 n = a125290_list !! (n-1)
    a125290_list = filter ((> 1) . a043537) a052382_list
    -- Reinhard Zumkeller, Jun 18 2013
    
  • Mathematica
    Select[Range[200], FreeQ[#, 0] && Length[Union[#]] > 1 & [IntegerDigits[#]] &] (* Paolo Xausa, May 06 2024 *)
  • Python
    def ok(n): s = set(str(n)); return len(s) >= 2 and "0" not in s
    print([k for k in range(124) if ok(k)]) # Michael S. Branicky, Dec 13 2021

Formula

A043537(A004719(a(n))) > 1.
A168046(a(n)) * A043537(A004719(a(n))) > 1. - Reinhard Zumkeller, Jun 18 2013
a(n) ~ n. - Charles R Greathouse IV, Feb 13 2017

Extensions

Name clarified by Michael S. Branicky, Dec 13 2021

A061828 Number of partitions of n into parts using the digits of n.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 8, 6, 5, 5, 4, 4, 4, 4, 2, 17, 2, 5, 8, 4, 6, 3, 5, 3, 2, 21, 9, 2, 4, 4, 8, 3, 3, 6, 2, 23, 17, 6, 2, 4, 5, 3, 8, 3, 2, 27, 11, 7, 5, 2, 3, 3, 3, 3, 2, 28, 21, 17, 9, 4, 2, 3, 4, 5, 2, 30, 12, 7, 5, 4, 3, 2, 3, 3, 2, 32, 23, 7, 17, 4, 6, 3, 2, 3, 2, 33, 13, 21, 6, 5, 9
Offset: 1

Views

Author

Amarnath Murthy, May 28 2001

Keywords

Examples

			a(20) = 2, the only partitions permitted are 20 and 2+2+2...ten times. a(21) = 16, 5 more than A061827 as the partition 12 + 2+2+2+2+1 etc. ( 5 in number) are also considered.
a(21) = 17. The allowed parts are 1, 2, 12 and 21. The 17 sums are 21, 12+2+2+2+2+1, 12+2+2+2+1+1+1, 12+2+2+1+1+1+1+1, 12+2+1+1+1+1+1+1+1, 12+1+1+1+1+1+1+1+1+1+1 and 11 more involving only 1 and 2.
		

Crossrefs

Cf. A061827.

Extensions

More terms from David Wasserman, Sep 01 2002

A136460 Number of partitions of n into parts which are not digits of n in decimal representation.

Original entry on oeis.org

0, 1, 2, 4, 6, 10, 14, 21, 29, 11, 13, 8, 10, 18, 23, 33, 40, 55, 64, 170, 35, 244, 119, 174, 234, 303, 384, 475, 577, 1215, 180, 399, 1844, 904, 1194, 1538, 1901, 2326, 2776, 5681, 719, 1517, 2391, 9042, 4426, 5594, 6877, 8286, 9819, 20481, 2184, 4599, 7187, 10050, 33591
Offset: 1

Views

Author

Reinhard Zumkeller, Dec 30 2007

Keywords

Examples

			a(12) = #{9+3,8+4,7+5,6+6,6+3+3,5+4+3,4+4+4,3+3+3+3} = 8;
a(13) = #{9+4,9+2+2,8+5,7+6,7+4+2,7+2+2+2,6+5+2,5+4+4,5+4+2+2,5+2+2+2+2} = 10.
		

Crossrefs

Cf. A061827.

Programs

  • PARI
    a(n)={my(S=Set(digits(n))); polcoef(1/prod(k=1, 9, 1 - if(!setsearch(S,k), x^k) + O(x*x^n)), n)} \\ Andrew Howroyd, Feb 02 2020

Extensions

Terms a(38) and beyond from Andrew Howroyd, Feb 02 2020

A193513 Number of partitions of n into parts having at least one common digit in decimal representation.

Original entry on oeis.org

1, 1, 2, 2, 3, 2, 4, 2, 4, 3, 4, 3, 8, 5, 9, 9, 13, 9, 16, 12, 18, 16, 23, 20, 31, 30, 38, 38, 51, 49, 64, 62, 79, 77, 95, 101, 118, 118, 143, 145, 179, 181, 216, 223, 267, 286, 325, 341, 399, 416, 485, 500, 575, 600, 686, 735, 823, 864, 981, 1032, 1180
Offset: 0

Views

Author

Reinhard Zumkeller, Jul 30 2011

Keywords

Examples

			a(7) = #{7, 7x1} = 2;
a(8) = #{8, 4+4, 2+2+2+2, 8x1} = 4;
a(9) = #{9, 3+3+3, 9x1} = 3;
a(10) = #{10, 5+5, 2+2+2+2+2, 10x1} = 4;
a(11) = #{11, 10+1, 11x1} = 3;
a(12) = #{12, 11+1, 10+1+1, 6+6, 4+4+4, 3+3+3+3, 6x2, 10x1} = 8;
a(13) = #{13, 12+1, 11+1+1, 10+1+1+1, 13x1} = 5;
a(14) = #{14, 13+1, 12+2, 12+1+1, 11+1+1+1, 10+4x1, 7+7, 7x2, 14x1} = 9.
		

Crossrefs

Programs

  • Haskell
    import Data.List (intersect)
    a193513 n = p "0123456789" n 1 where
       p ""        = 0
       p   0       = 1
       p cds m k
         | m < k     = 0
         | otherwise = p (cds `intersect` show k) (m - k) k + p cds m (k + 1)

Extensions

Thanks to Douglas McNeil, who noticed a program error; data corrected and program fixed by Reinhard Zumkeller, Aug 01 2011
Showing 1-8 of 8 results.