This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A115927 a(n) is the number of k such that k and n*k, taken together, are pandigital. 11

%I

%S 0,48,6,8,12,0,1,16,3,0,0,1,1,6,3,1,19,6,4,12,0,3,3,4,3,9,2,1,8,2,0,

%T 16,1,3,14,0,3,7,3,4,0,3,1,13,4,1,6,0,1,12,0,2,28,1,4,6,1,3,6,3,0,28,

%U 1,1,10,1,1,4,5,7,0,3,3,11,0,2,8,1,1,46,0,0,5,3,1,7,5,6,8,3,0,13,2,3

%N a(n) is the number of k such that k and n*k, taken together, are pandigital.

%C There are 1549586 nonzero terms in a(n). The largest n for which a(n) > 0 is 987654320. The largest a(n) is a(2) = 48. - _Chai Wah Wu_, May 24 2015

%H Chai Wah Wu, <a href="/A115927/b115927.txt">Table of n, a(n) for n = 1..10000</a>

%e a(7)=1 since there is only one number, k=14076, such that k and 7*k=98532.

%e a(9)=3 since there are 3 such numbers: 10638, 10647 and 10836.

%o (Python)

%o from itertools import permutations

%o l = {}

%o for d in permutations('0123456789', 10):

%o ....if d[0] != '0':

%o ........for i in range(9):

%o ............if d[i+1] != '0':

%o ................q, r = divmod(int(''.join(d[:i+1])),int(''.join(d[i+1:])))

%o ................if not r:

%o ....................if q in l:

%o ........................l[q] += 1

%o ....................else:

%o ........................l[q] = 1

%o A115927_list = [0]*max(l)

%o for d in l:

%o ....A115927_list[d-1] = l[d] # _Chai Wah Wu_, May 24 2015

%Y Cf. A054383, A115922, A115923, A115924, A115925, A114126.

%K nonn,base

%O 1,2

%A _Giovanni Resta_, Feb 06 2006

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

Last modified December 8 01:46 EST 2019. Contains 329850 sequences. (Running on oeis4.)