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 1-3 of 3 results.

A328287 Number of multiples of n which have only distinct and nonzero digits in base 10.

Original entry on oeis.org

0, 986409, 438404, 572175, 219202, 109601, 255752, 140515, 109601, 432645, 0, 90212, 127163, 75768, 62436, 65027, 56104, 57930, 194244, 51869, 0, 81493, 40572, 42969, 63654, 27400, 33587, 145926, 31217, 34146, 0, 31827, 27926, 51090, 25772, 15702, 97114, 26330, 23106, 43929, 0, 23983, 36409
Offset: 0

Views

Author

M. F. Hasler, Oct 10 2019

Keywords

Comments

This is column 0 of A328288, extension of A328277.
No term can exceed a(1), cf. example. The sequence is finite in the sense that a(n) = 0 for n > 987654321, since one cannot have more than 9 distinct nonzero digits.
See A328290 for generalization to other bases.

Examples

			For n = 1, this is simply the number of numbers with only distinct and nonzero digits. All other terms are less than a(1), namely, the size of the subset of these numbers which are multiples of n.
		

Crossrefs

This is row 10 of A328290.

Programs

  • PARI
    A328287(n,B=10,S)={for(L=1,B-1,my(T=vectorv(L,k,B^(k-1))); forperm(L,p,u=vecextract(T,p);forvec(d=vector(L,i,[1,B-1]),d*u%n||S++,2)));S} \\ 2nd optional argument allows to specify a base different from 10
    
  • PARI
    See Links section

Formula

a(n) = 0 whenever n == 0 (mod 10) or n > 987654321.

A328288 Triangle T(m,n) = # { k | concat(mk,nk) has no digit twice or more }, m >= n >= 0.

Original entry on oeis.org

0, 986409, 0, 438404, 304, 0, 572175, 153, 157, 0, 219202, 197, 124, 97, 0, 109601, 221, 156, 69, 171, 0, 255752, 73, 88, 142, 68, 69, 0, 140515, 129, 73, 81, 86, 62, 46, 0, 109601, 189, 88, 40, 67, 48, 51, 24, 0, 432645, 89, 80, 77, 31, 63, 68, 41, 20, 0, 0, 0, 132, 80, 90, 58, 32, 63, 99, 37, 0
Offset: 0

Views

Author

M. F. Hasler, Oct 10 2019

Keywords

Comments

This is an extended version of A328277 which is restricted to m > n >= 1.
One may consider T(m,n) defined for all m, n >= 0, which would yield a symmetric, infinite square array T(m,n), see formula.
For m and/or n = 0, see A328287(n) = T(0,n) = T(n,0), n >= 0.
The table is finite in the sense that T(m,n) = 0 for m > 987654321 (even if the multiple isn't pandigital, (mk, nk) cannot have more than 9+1 distinct digits), but also whenever the total number of digits of m and n exceeds 10.

Examples

			The table reads :
       0,    (m=0)
  986409, 0,      (m=1)
  438404, 304,   0,    (m=2)
  572175, 153, 157,   0,    (m=3)
  219202, 197, 124,  97,   0,   (m=4)
  109601, 221, 156,  69, 171,  0,   (m=5)
  255752,  73,  88, 142,  68, 69,  0,   (m=6)
  140515, 129,  73,  81,  86, 62, 46,  0,   (m=7)
  109601, 189,  88,  40,  67, 48, 51, 24,  0,   (m=8)
  432645,  89,  80,  77,  31, 63, 68, 41, 20,  0,   (m=9)
       0,   0, 132,  80,  90, 58, 32, 63, 99, 37,  0,   (m=10)
   90212,   0, 106,  69,  79, 50, 30, 45, 30, 38,  0,  0,    (m=11)
  127163,  76,   0,  96,  31, 62, 54, 27, 31, 49, 41, 27,   0,   (m=12)
   75768,  84,  72,   0,  31, 58, 47, 26, 23, 34, 43, 25, 20,   0,  (m=13)
   62436, 100,  64,  52,   0, 51, 44, 51, 42, 22, 38, 27, 18, 20   0,  (m=14)
  ...
The terms corresponding to T(2,1) = 304 and T(3,1) = 153 are given in Eric Angelini's post to the SeqFan list.
Column 0 is A328287 (number of multiples of m that have only distinct and nonzero digits).
		

Programs

Formula

T(m,n) = 0 whenever m == n (mod 10).
T(m,n) = T(n,m) for all m, n >= 0, if the condition m > n is dropped.

A328290 Table T(b,n) = #{ k > 0 | nk has only distinct and nonzero digits in base b }, b >= 2, 1 <= n <= A051846(b).

Original entry on oeis.org

1, 4, 1, 0, 0, 1, 0, 1, 15, 5, 9, 0, 2, 3, 2, 0, 4, 1, 1, 0, 2, 1, 2, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 64, 42, 21, 9, 0, 14, 8, 4, 7, 0, 6, 4, 3, 6, 0, 3, 2, 5, 2, 0, 4, 5, 3, 2, 0, 0, 2, 1, 2, 0, 2, 1, 2, 1, 0, 1, 2, 1, 2, 0, 1, 3, 1, 1, 0, 1, 1, 2, 1, 0, 0, 0, 0, 2
Offset: 2

Views

Author

M. F. Hasler, Oct 11 2019

Keywords

Comments

The table could also be considered as an infinite square array with T(b,n) = 0 for n > A051846(b) = the largest pandigital number in base b.
Can anyone find a simple formula for the index of the last terms > 1 in each row b?

Examples

			The table reads:  (column n >= 2 corresponds to the base)
   B \ n = 1      2      3      4      5      6      7     8      9      10  ...
   2       1     (0 ...)
   3       4      1      0      0      1      0      1    (0 ...)
   4      15      5      9      0      2      3      2     0      4       1  ...
   5      64     42     21      9      0     14      8     4      7       0  ...
   6     325    130     65     65    161      0     48    23     32      66  ...
   7    1956    651   1140    319    386    221      0   156    362     128  ...
   8   13699   5871   4506   1957   2748   1944   6277     0   1470    1189  ...
   9  109600  73588  27400  56930  21973  18397  15641  8305      0   14826  ...
  10  986409 438404 572175 219202 109601 255752 140515 109601 432645     0   ...
  (...)
In base 2, 1 is the only number with distinct nonzero digits, so T(2,1) = 1, T(2,n) = 0 for n > 1.
In base 3, {1, 2, 12_3 = 5, 21_3 = 7} are the only numbers with distinct nonzero digits, so T(3,1) = 4, T(3,2) = T(3,7) = T(3,7) = 1, T(3,n) = 0 for n > 7.
In base 4, {1, 2, 3, 12_4 = 6, 13_4 = 7, 21_4 = 9, ..., 321_4 = 57} are the only numbers with distinct nonzero digits, so T(4,n) = 0 for n > 57.
		

Crossrefs

Cf. A328287 (row 10), A328288, A328277.
Column 1 is A007526 (number of nonnull variations of n distinct objects).

Programs

  • PARI
    T(B,n)={my(S,T,U); for(L=1,B-1,T=vectorv(L,k,B^(k-1)); forperm(L,p, U=vecextract(T,p); forvec(D=vector(L,i,[1,B-1]),D*U%n||S++,2)));S}

Formula

T(b,b) = 0, since any multiple of b has a trailing digit 0 in base b.
T(b,A051846(b)) = 1 and T(b,n) = 0 for n > A051846(b) = (b-1)(b-2)..21 in base b.
Showing 1-3 of 3 results.