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 1-4 of 4 results.

A178485 (A178475(n)-6)/9.

Original entry on oeis.org

1371, 1372, 1381, 1383, 1392, 1393, 1471, 1472, 1491, 1494, 1502, 1504, 1581, 1583, 1591, 1594, 1613, 1614, 1692, 1693, 1702, 1704, 1713, 1714, 2371, 2372, 2381, 2383, 2392, 2393, 2571, 2572, 2601, 2605, 2612, 2615, 2681, 2683, 2701, 2705, 2723, 2725
Offset: 1

Views

Author

M. F. Hasler, May 28 2010

Keywords

Comments

There are 5!=120 terms in this finite sequence. Its origin is the fact that numbers whose decimal expansion is a permutation of 12345 are all of the form 9k+6.

Crossrefs

Programs

  • PARI
    v=vector(5,i,10^(i-1))~; vecsort(vector(5!,i,numtoperm(5,i)*v))
    is_A178475(x)= { vecsort(Vec(Str(x)))==Vec("12345") }
    forstep( m=12345,54321,9, is_A178475(m) & print1(m","))

Formula

a(n) + a(5!+1-n) = 7406.
a(n) == 1, 2, 3, 4 or 5 (mod 10).
a(n+6)-a(n) is an element of { 100, 110, 111, 200, 220, 222, 679 }.
a(n+6)-a(n) = 679 iff (n-1)%24 > 17, where % denotes the remainder upon division.
a(n+6)-a(n) = 200, 220 or 222 iff (n-1)%30 > 23, i.e. n==25,...,30 (mod 30).

A178486 (A178476(n)-3)/9.

Original entry on oeis.org

13717, 13718, 13727, 13729, 13738, 13739, 13817, 13818, 13837, 13840, 13848, 13850, 13927, 13929, 13937, 13940, 13959, 13960, 14038, 14039, 14048, 14050, 14059, 14060, 14717, 14718, 14727, 14729, 14738, 14739, 14917, 14918, 14947, 14951, 14958, 14961
Offset: 1

Views

Author

M. F. Hasler, May 28 2010

Keywords

Comments

The sequence is motivated by the fact that numbers whose decimal expansion is a permutation of 123456, are all of the form 9k+3.
There are 6!=720 terms in this finite sequence.

Crossrefs

Programs

  • PARI
    forstep( m=123456,654321/*or less*/,9, is_A178476(m) & print1(m\9",")) /*cf. A178476*/

Formula

a(n) + a(6!+1-n) = 86419.
a(n) == 0, 1, 2, 7, 8 or 9 (mod 10).

A178478 Permutations of 12345678: Numbers having each of the decimal digits 1..8 exactly once, and no other digit.

Original entry on oeis.org

12345678, 12345687, 12345768, 12345786, 12345867, 12345876, 12346578, 12346587, 12346758, 12346785, 12346857, 12346875, 12347568, 12347586, 12347658, 12347685, 12347856, 12347865, 12348567, 12348576, 12348657, 12348675, 12348756, 12348765
Offset: 1

Views

Author

M. F. Hasler, Oct 09 2010

Keywords

Comments

It would be nice to have a simple explicit formula for the n-th term.
An efficient procedure for generating the n-th term of this sequence can be found at A178475. - Nathaniel Johnston, May 19 2011

Crossrefs

Programs

  • Mathematica
    Take[FromDigits/@Permutations[Range[8]],40] (* Harvey P. Dale, Oct 29 2014 *)
  • PARI
    is_A178478(x)= { vecsort(Vec(Str(x)))==Vec("12345678") }
    
  • PARI
    A178478(n)={my(b=vector(7,k,1+(n-1)%(k+1)!\k!),t=b[7], d=vector(7,i,i+(i>=t)));for(i=1,6,t=10*t+d[b[7-i]]; d=vecextract(d,Str("^"b[7-i]))); t*10+d[1]} \\ - M. F. Hasler (following N. Johnston's comment), Jan 10 2012

A191819 (A178477(n)-1)/9.

Original entry on oeis.org

137174, 137175, 137184, 137186, 137195, 137196, 137274, 137275, 137294, 137297, 137305, 137307, 137384, 137386, 137394, 137397, 137416, 137417, 137495, 137496, 137505, 137507, 137516, 137517, 138174, 138175, 138184, 138186, 138195, 138196, 138374, 138375, 138404
Offset: 1

Views

Author

Nathaniel Johnston, Jun 24 2011

Keywords

Comments

The sequence is motivated by the fact that numbers whose decimal expansion is a permutation of 1234567 are all of the form 9k+1.

Crossrefs

Showing 1-4 of 4 results.