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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A287513 Numbers whose cyclic permutations are pairwise coprime.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 13, 14, 16, 17, 19, 23, 25, 29, 31, 32, 34, 35, 37, 38, 41, 43, 47, 49, 52, 53, 56, 58, 59, 61, 65, 67, 71, 73, 74, 76, 79, 83, 85, 89, 91, 92, 94, 95, 97, 98, 112, 113, 115, 116, 118, 119, 121, 125, 127, 131, 133, 134, 136, 137
Offset: 1

Views

Author

Rémy Sigrist, May 26 2017

Keywords

Comments

No term, except 10, contains a '0' digit.
No term contains two even digits.
No term > 9 is a multiple of 3.
No term contains two '5' digits.
This sequence contains A287198.
This sequence does not contain any term > 9 of A084433.
In the scatterplot of the first 10000 terms:
- the jump from a(7128) = 99998 to a(7129) = 111112 is due to the fact that there is no term > 10 starting with "10",
- the dotted lines, for example between a(2545) = 21131 and a(2772) = 29999, are due to the fact that there is no term starting with two even digits,
- these features can be seen at different scales (see scatterplots in Links section).

Examples

			The cyclic permutations of 5992 are:
- 5992 = 2^3 * 7 * 107
- 9925 = 5^2 * 397
- 9259 = 47 * 197
- 2599 = 23 * 113.
These values are pairwise coprime, hence 5992 appear in the sequence.
The cyclic permutations of 5776 are:
- 5776 = 2^4 * 19^2,
- 7765 = 5 * 1553,
- 7657 = 13 * 19 * 31,
- 6577 = 6577.
gcd(5776, 7657) = 19, hence 5776 does not appear in the sequence.
		

Crossrefs

Programs

  • Mathematica
    A287513Q[k_] := k < 10 || CoprimeQ @@ Map[FromDigits, NestList[RotateLeft, #, Length[#] - 1] & [IntegerDigits[k]]];
    Select[Range[200], A287513Q] (* Paolo Xausa, Aug 27 2025 *)
  • PARI
    is(n) = my (p=n, l=#digits(n)); for (k=1, l-1, n = (n\10) + (n%10)*(10^(l-1)); if (gcd(n, p)>1, return (0)); p = lcm(n, p);); return (1)

A287478 Positive numbers m with the property that m is the least cyclic permutation of its digits with the same number of digits as m.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 33, 34, 35, 36, 37, 38, 39, 40, 44, 45, 46, 47, 48, 49, 50, 55, 56, 57, 58, 59, 60, 66, 67, 68, 69, 70, 77, 78, 79, 80, 88, 89, 90, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120
Offset: 1

Views

Author

David A. Corneth, May 25 2017

Keywords

Comments

First differs from A179239 at n = 83; a(83) = 120 and A179239(83) = 122. This sequence is a supersequence of A179239.
If there is a zero digit, then we do not consider the cyclic shift which begins with the zero digit.
The number 0 should also be in this list. The initial digit of any term must be its smallest nonzero digit. - M. F. Hasler, Oct 18 2019

Crossrefs

Programs

  • Mathematica
    Select[Range@ 120, Function[d, First@ Sort@ Map[FromDigits, DeleteCases[ NestList[RotateLeft, d, Length@ d - 1], ?(First@ # == 0 &)]] == #]@ IntegerDigits@ # &] (* _Michael De Vlieger, May 27 2017 *)
  • PARI
    is(n) = my(d=digits(n), v=vector(#d), no=n, nn=n, l=List(n)); for(i=2,#d, no = nn\10; no = no+(nn-no*10)*10^(#d-1); if(#digits(no)==#d,listput(l, no)); nn=no); listsort(l); n==l[1]
    is(n) = {my(d = digits(n), dd = concat(d, d)); for(i=2,#d, c=vector(#d, j, dd[i+j-1]); if(fromdigits(c) < n, if(c[1]!=0, return(0)))); 1}
    
  • PARI
    is_A287478(n,D=digits(n))={!for(i=2,#D,((D[i]M. F. Hasler, Oct 18 2019
Showing 1-2 of 2 results.