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.

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A260217 Number of base-3 n-digit pandigital numbers.

Original entry on oeis.org

0, 0, 4, 24, 100, 360, 1204, 3864, 12100, 37320, 114004, 346104, 1046500, 3155880, 9500404, 28566744, 85831300, 257756040, 773792404, 2322425784, 6969374500, 20912317800, 62745342004, 188252803224, 564791964100, 1694443001160, 5083463221204, 15250658099064
Offset: 1

Views

Author

Jon E. Schoenfield, Jul 19 2015

Keywords

Comments

From Manfred Boergens, Aug 02 2023: (Start)
a(n+1) is the number of pairs (A,B) where A and B are nonempty subsets of {1,2,...,n} and one of these subsets is a proper subset of the other.
If "proper" is omitted, see A091344.
If empty subsets are included, see A027649 (all subsets) and A056182 (proper subsets). (End)

Examples

			a(3)=4 because, in base 3, there are four 3-digit pandigital numbers (11=102_3, 15=120_3, 19=201_3, and 21=210_3).
a(4)=24 because, in base 3, there are 24 4-digit pandigital numbers (1002_3, 1012_3, 1020_3, 1021_3, 1022_3, 1102_3, 1120_3, 1200_3, 1201_3, 1202_3, 1210_3, 1220_3, 2001_3, 2010_3, 2011_3, 2012_3, 2021_3, 2100_3, 2101_3, 2102_3, 2110_3, 2120_3, 2201_3, and 2210_3).
		

Crossrefs

Programs

  • Magma
    [2*3^(n-1) - 2^(n+1) + 2: n in [1..30]]; // Vincenzo Librandi, Jul 20 2015
  • Mathematica
    Table[2 3^(n - 1) - 2^(n + 1) + 2, {n, 30}] (* Vincenzo Librandi, Jul 20 2015 *)

Formula

a(n) = 2*A028243(n) = 2*3^(n-1) - 2^(n+1) + 2.
a(n) = 4*A000392(n).
G.f.: 4*x^3/((1-x)*(1-2*x)*(1-3*x)).
E.g.f.: 2/3*((exp(x)-1)^3).

A277054 Least k such that n-th repunit times k is a pandigital.

Original entry on oeis.org

1023456789, 93125079, 9222117, 1110789, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115, 92115
Offset: 1

Views

Author

Andrey Zabolotskiy and Altug Alkan, Sep 26 2016

Keywords

Comments

Starting from n=5, a(n)=A277056(10)=92115, and the corresponding pandigitals are 1023499...989765 (n-5 nines).
a(1)-a(5) constitute row 10 of A277055.
a(n)*A002275(n) is 1023456789, 1024375869, 1023654987, 1234086579, 1023489765, ...

Examples

			a(2) = 93125079 because A002275(2)*93125079 = 11*93125079 = 1024375869 that is a pandigital and 93125079 is the least number with this property.
		

Crossrefs

A277055 Irregular array by rows: A(n,m) is the least number which gives a pandigital product when multiplied by the m-th repunit in base n; each row is truncated when it reaches its stationary point.

Original entry on oeis.org

2, 11, 8, 5, 75, 15, 7, 694, 119, 34, 8345, 1505, 195, 123717, 105803, 2217, 2134, 727, 2177399, 241934, 37303, 3724, 44317196, 4431858, 487068, 54771, 9124, 1023456789, 93125079, 9222117, 1110789, 92115, 26432593615
Offset: 2

Views

Author

Andrey Zabolotskiy and Altug Alkan, Sep 26 2016

Keywords

Comments

For row n, the initial number is A049363(n) and the trailing number is A277056(n). Row 10 is A277054(1)-A277054(5) [note that the initial row is row 2].

Examples

			The first rows of the array are:
2, (2, 2...)
11, 8, 5, (5, 5...)
75, 15, 7, (7, 7...)
694, 119, 34,
8345, 1505, 195,
123717, 105803, 2217, 2134, 727,
2177399, 241934, 37303, 3724,
44317196, 4431858, 487068, 54771, 9124,
1023456789, 93125079, 9222117, 1110789, 92115
		

Crossrefs

A277056 Least k such that any sufficiently long repunit multiplied by k is a pandigital number in numerical base n.

Original entry on oeis.org

2, 5, 7, 34, 195, 727, 3724, 9124, 92115, 338161, 2780514, 6871290, 99000993
Offset: 2

Views

Author

Andrey Zabolotskiy and Altug Alkan, Sep 26 2016

Keywords

Comments

Trailing terms of rows of A277055.
Written in base n, the terms read: 10, 12, 13, 114, 523, 2056, 7214, 13457, 92115, 21107A, B21116, 156776A, D211117, ...

Examples

			Any binary repunit multiplied by 2 is a binary pandigital, so a(2)=2 (10 in binary).
k-th decimal repunit for k>4 multiplied by 92115 gives a decimal pandigital number (see A277054) with no number less than 92115 having the same property, so a(10)=92115.
		

Crossrefs

Formula

Conjecture: for even n>4, a(n) = (n-2)*n^(n/2-1) + n^(n/2-2) + (n^(n/2)-1)/(n-1) + n/2 - 1.

A337127 Table with 10 columns read by rows: T(n, k) is the number of n-digit positive integers with exactly k distinct base 10 digits (0 < k <= 10).

Original entry on oeis.org

9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 9, 81, 0, 0, 0, 0, 0, 0, 0, 0, 9, 243, 648, 0, 0, 0, 0, 0, 0, 0, 9, 567, 3888, 4536, 0, 0, 0, 0, 0, 0, 9, 1215, 16200, 45360, 27216, 0, 0, 0, 0, 0, 9, 2511, 58320, 294840, 408240, 136080, 0, 0, 0, 0, 9, 5103, 195048, 1587600, 3810240, 2857680, 544320, 0, 0, 0
Offset: 1

Views

Author

Stefano Spezia, Aug 17 2020

Keywords

Examples

			The table T(n, k) begins:
9     0      0       0       0       0  0  0  0  0
9    81      0       0       0       0  0  0  0  0
9   243    648       0       0       0  0  0  0  0
9   567   3888    4536       0       0  0  0  0  0
9  1215  16200   45360   27216       0  0  0  0  0
9  2511  58320  294840  408240  136080  0  0  0  0
...
		

Crossrefs

Cf. A010734, A048993, A052268 (row sums), A073531 (diagonal), A180599 (k = 1), A335843 (k = 2), A337313 (k = 3).

Programs

  • Mathematica
    T[n_,k_]:=9Pochhammer[11-k,k-1]/k!*n!*Coefficient[Series[(Exp[x]-1)^k,{x,0,n}],x,n]; Table[T[n,k],{n,7},{k,10}]//Flatten

Formula

T(n, k) = 9*Pochhammer(11-k, k-1)*n! * [x^n] (exp(x) - 1)^k/k!.
T(n, k) = 9*Pochhammer(11-k, k-1) * [x^n] x^k/Product_{j=1..k} (1-j*x).
T(n, k) = 9*Pochhammer(11-k, k-1)*S2(n, k) where S2(n, k) = A048993(n, k) are the Stirling numbers of the 2nd kind.

A358097 a(n) is the smallest integer m > n such that m and n have no common digit, or -1 when such integer m does not exist.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 22, 20, 30, 20, 20, 20, 20, 20, 20, 20, 31, 30, 30, 40, 30, 30, 30, 30, 30, 30, 41, 40, 40, 40, 50, 40, 40, 40, 40, 40, 51, 50, 50, 50, 50, 60, 50, 50, 50, 50, 61, 60, 60, 60, 60, 60, 70, 60, 60, 60, 71, 70, 70, 70, 70, 70, 70, 80, 70, 70, 81, 80, 80, 80, 80
Offset: 0

Views

Author

Bernard Schott, Oct 29 2022

Keywords

Comments

When n is pandigital with or without 0 (A050278, A050289, A171102), m does not exist, so a(n) = -1; see examples for smallest pandigital cases.

Examples

			a(10) = 22; a(11) = 20; a(12) = 30.
a(123456789) = -1; a(1234567890) = -1.
		

Crossrefs

Cf. A030283 (trajectory starting 0).
Cf. A358098 (similar, with largest integer m < n).

Programs

  • Mathematica
    a[n_] := Module[{d = Complement[Range[0, 9], IntegerDigits[n]], m = n + 1}, If[d == {} || d == {0}, -1, While[! AllTrue[IntegerDigits[m], MemberQ[d, #] &], m++]; m]]; Array[a, 100, 0] (* Amiram Eldar, Oct 29 2022 *)
  • PARI
    isfull(d) = my(dd=setminus([0..9], d)); (dd==[]) || (dd==[0]);
    a(n) = my(d=Set(digits(n))); if (isfull(d), -1, my(k=n+1); while (#setintersect(Set(digits(k)), d), k++); k); \\ Michel Marcus, Oct 29 2022
    
  • Python
    from itertools import count, product
    def a(n):
        s = str(n)
        r = sorted(set("1234567890") - set(s))
        if len(r) == 0 or r == ["0"]: return -1
        for d in count(len(s)):
            for p in product(r, repeat=d):
                m = int("".join(p))
                if m > n: return m
    print([a(n) for n in range(75)]) # Michael S. Branicky, Oct 29 2022

Formula

a(10^n-k) = 10^n when n >= 2 and 1 <= k <= 8.
a(10^n) = 2 * A002275(n+1), when n >= 1.

A217110 Number of pandigital numbers with n places.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 0, 3265920, 179625600, 5568393600, 128432304000, 2458427811840, 41355201888000, 632788296940800, 9008498667168000, 121205358007493760, 1558813928579107200, 19326359087766057600, 232491479092720848000, 2727512837264447527680, 31331281164921975283200, 353549170783043484480000
Offset: 1

Views

Author

Hieronymus Fischer, Feb 13 2013

Keywords

Comments

The number of numbers between 10^(n-1) and 10^n which contain all decimal digits 0..9.
The ratio a(n)/(10^n-10^(n-1)) indicates the relative proportion of pandigital n-digit numbers compared to all n-digit numbers. Since that ratio converges to the limit 1 for n->oo this can be expressed for large numbers as follows (in a slightly popular manner): "Almost all numbers contain all decimal digits 0..9".
Example: a(n)/(10^n-10^(n-1)) = 0.99973439517775... for n = 100; in this case 99.9734...% of all 100-digit numbers contain all digits 0..9. Conversely, only the tiny proportion of 0.00026560482224... (< 0.03%) lacks one digit. That's astonishing! Intuitively, this is not what one would expect. In fact, for smaller numbers (with which most people are faced normally) the relative portion of numbers which missing at least one digit is significantly larger. Of course, for n < 10 the portion is 100%, and even for numbers with n = 10 or 20 digits the relative proportion of numbers which do not contain all digits 0..9 is 99.96371...% or 78.52626...%, respectively. The least number of digits for which the pandigital numbers hold the majority is 27. Here, the proportion of numbers which do not contain all digits is 48.03664...%. So one could bet that a randomly chosen number with >= 27 digits contains all digits.

Examples

			a(k) = 0 for k < 10 since there are no pandigital numbers with < 10 places, trivially.
a(10) = 9*9! since the first digit can be in the range 1..9 and for the following 9 digits there are 9, 8, 7, ..., 1 possible values.
		

Crossrefs

Formula

a(n) = 9*9!*S2(n,10), where the S2(n,10) are the Stirling numbers of the second kind (cf. triangle A008277).
Asymptotic behavior: Limit_{n->oo} a(n)/10^n = 9/10.
G.f.: g(x) = 9*9!*x^10/(Product_{j=1..10} (1-jx)).
E.g.f. g(x) = (9/10) * (e^x - 1)^10.

A226273 Number of distinct values u^v, where u and v are digits occurring in decimal representation of n.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 4, 3, 4, 4, 4, 4, 4, 3, 3, 4, 1, 4, 4, 4, 4, 4, 4, 3, 3, 3, 4, 1, 4, 4, 4, 4, 4, 3, 3, 4, 4, 4, 1, 4, 4, 4, 4, 3, 3, 4, 4, 4, 4, 1, 4, 4, 4, 3, 3, 4, 4, 4, 4, 4, 1, 4, 4, 3, 3, 4, 4, 4, 4
Offset: 0

Views

Author

Reinhard Zumkeller, Jul 09 2013

Keywords

Comments

Row lengths in table A226272;
a(n) <= 61; A171102(1) = 1023456789 is the smallest number m such that a(m) = 61.
a(n) = 61 for almost all n, in the sense that the natural density of n such that a(n) < 61 is 0. - Charles R Greathouse IV, May 13 2015

Examples

			See A226272.
		

Programs

  • Haskell
    a226273 = length . a226272_row :: Integer -> Int
    
  • PARI
    a(n)=if(n<9, return(1)); my(d=Set(digits(n)),v=List()); for(i=1,#d, for(j=1,#d, listput(v,d[i]^d[j]))); #Set(v) \\ Charles R Greathouse IV, May 13 2015

A262277 Numbers having in decimal representation the same distinct decimal digits as their 9's complement.

Original entry on oeis.org

18, 27, 36, 45, 54, 63, 72, 81, 90, 118, 181, 188, 227, 272, 277, 336, 363, 366, 445, 454, 455, 544, 545, 554, 633, 636, 663, 722, 727, 772, 811, 818, 881, 900, 909, 990, 1089, 1098, 1118, 1181, 1188, 1278, 1287, 1368, 1386, 1458, 1485, 1548, 1584, 1638
Offset: 1

Views

Author

Reinhard Zumkeller, Sep 17 2015

Keywords

Comments

If d is a digit of any term then also 9 - d;

Crossrefs

Cf. A061601, A227362, subsequences: A111708, A050278, A171102.

Programs

  • Haskell
    import Data.List (nub, sort)
    a262277 n = a262277_list !! (n-1)
    a262277_list = filter f [1..] where
       f x = sort ds' == sort (map (9 -) ds') where
         ds' = nub $ ds x
         ds 0 = []; ds z = d : ds z' where (z', d) = divMod z 10
    
  • PARI
    isok(m) = my(d=digits(m), c=apply(x->9-x, d)); Set(d) == Set(c); \\ Michel Marcus, Jan 22 2022

Formula

A227362(A061601(a(n))) = A227362(a(n)).

A272269 Numbers n such that 11^n does not contain all ten decimal digits.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 25, 27, 28, 34, 38, 41
Offset: 1

Views

Author

Altug Alkan, Apr 24 2016

Keywords

Comments

Inspiration was the simple form of 11 that is concatenation of 1 and 1. With similar motivation, A130696 focuses on the values of 2^n = (1 + 1)^n. Since this sequence exists in base 10, 11^n*10 is simply concatenation of 11^n and 0. So 11^(n+1) = concat(11^n, 0) + 11^n while 2^(n+1) = 2^n + 2^n.
A030706 is a subsequence. So note that if there is currently no proof of finiteness of A030706, then there is no proof yet of the finiteness of this sequence.

Examples

			25 is a term because 11^25 = 108347059433883722041830251 that does not contain digit 6.
26 is not a term because 11^26 = 11^25*10 + 11^25 = 1083470594338837220418302510 + 108347059433883722041830251 = 1191817653772720942460132761 that contains all ten decimal digits.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[0, 120], AnyTrue[DigitCount[11^#], # == 0 &] &] (* Michael De Vlieger, Apr 24 2016, Version 10 *)
  • PARI
    isA171102(n) = 9<#vecsort(Vecsmall(Str(n)), , 8);
    lista(nn) = for(n=0, nn, if(!isA171102(11^n), print1(n, ", ")));
    
  • PARI
    select( is_A272269(n)=#Set(digits(11^n))<10 ,[0..100]) \\ M. F. Hasler, May 18 2017
Previous Showing 31-40 of 74 results. Next