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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A270083 Near-miss circular primes: Primes p where all but one of the numbers obtained by cyclically permuting the digits of p are prime.

Original entry on oeis.org

19, 23, 29, 41, 43, 47, 53, 59, 61, 67, 83, 89, 101, 103, 107, 127, 149, 157, 163, 173, 181, 191, 271, 277, 307, 313, 317, 331, 359, 367, 379, 397, 419, 479, 491, 571, 577, 593, 617, 631, 673, 701, 709, 727, 739, 757, 761, 787, 797, 811, 839, 877, 907, 911
Offset: 1

Views

Author

Felix Fröhlich, Mar 10 2016

Keywords

Comments

Prime p is a term of the sequence iff A262988(p) = A055642(p) - 1.
If a(512) exists, it is larger than 10^16. - Giovanni Resta, Apr 27 2017
If one of the digits is even or 5, the miss occurs when that digit is permuted to the ones place. Avoiding that simple obstruction, this sequence intersected with A091633 is 19, 173, 191, 313, 317, 331, 379, 397, 739, 797, 911, 937, 977, 1319, 1777, 1913, 1979, 1993, 3191, 3373, 3719, 3733, 3793, ... . Is this an infinite subsequence? - Danny Rorabaugh, May 15 2017

Links

Crossrefs

Cf. A045978, A068652, A262988.

Programs

A262988 Number of distinct primes, including n if prime, obtained by cyclically shifting the digits of n.

Original entry on oeis.org

0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 2, 1, 0, 1, 2, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 2, 1, 0, 1, 1, 0, 2, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 2, 0, 2, 1, 0, 1, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 0
Offset: 1

Views

Author

Felix Fröhlich, Oct 06 2015

Keywords

Comments

First differs from A039999 at n = 103.
Differs from A061264 iff n is a term of A004022.
a(n) = A055642(n) iff n is a term of A068652, except when n is also in A004022.

Examples

			a(1013) = 2, because of the four cyclic permutations of the digits of 1013 (1013, 131, 1310, 3101) two, namely 1013 and 131, are prime and those two primes are distinct.

Links

Crossrefs

Cf. A016114, A039999, A045978, A061264, A068652, A068653, A068654, A069219, A247153.

Programs

  • Mathematica
    f[n_] := Block[{len = IntegerLength@ n, s = {n}}, Do[AppendTo[s, FromDigits@ RotateRight@ IntegerDigits@ s[[k - 1]]], {k, 2, len}]; DeleteDuplicates@ Select[s, PrimeQ]]; Array[ Length@ f@ # &, {87}] (* Michael De Vlieger, Oct 07 2015 *)
  • PARI
    rot(n) = if(#Str(n)==1, v=vector(1), v=vector(#n-1)); for(i=2, #n, v[i-1]=n[i]); u=vector(#n); for(i=1, #n, u[i]=n[i]); v=concat(v, u[1]); v
eva(n) = x=0; for(k=1, #n, x=x+(n[k]*10^(#n-k))); x
a(n) = i=0; r=rot(digits(n)); while(r!=digits(n), if(ispseudoprime(eva(r)), i++); r=rot(r)); if(ispseudoprime(eva(r)), i++); i

A172435 Partial sums of circular primes A016114.

Original entry on oeis.org

2, 5, 10, 17, 28, 41, 58, 95, 174, 287, 484, 683, 1020, 2213, 5992, 17931, 37868, 231807, 431740, 1111111111111542851, 11112222222222222653962
Offset: 1

Views

Author

Jonathan Vos Post, Feb 02 2010

Keywords

Comments

Circular primes are a generalization of palindromatic primes (A002385): numbers which remain prime under cyclic shifts of digits. 484 is the first square partial sum of circular primes. The subsequence of prime partial sums of circular primes begins: 2, 5, 17, 41, 683, 2213. The subsubsequence of circular prime partial sums of circular primes begins 2, 5, 17, and what is the next? What are the analogs in other bases?

Examples

			a(21) = 2 + 3 + 5 + 7 + 11 + 13 + 17 + 37 + 79 + 113 + 197 + 199 + 337 + 1193 + 3779 + 11939 + 19937 + 193939 + 199933 + 1111111111111111111 + 11111111111111111111111.

Crossrefs

Cf. A000040, A002385, A004023, A003459, A016114, A045978, A068652.
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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