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.

User: Alvin Hoover Belt

Alvin Hoover Belt's wiki page.

Alvin Hoover Belt has authored 3 sequences.

A208362 "2-ply" palindromic primes.

Original entry on oeis.org

11, 101, 131, 151, 181, 191, 313, 353, 373, 383, 727, 757, 787, 797, 919, 929, 10301, 10501, 10601, 11311, 11411, 12421, 12721, 12821, 13331, 13831, 13931, 14341, 14741, 15451, 15551, 16061, 16361, 16561, 16661, 17471, 17971, 18181, 18481, 19391, 19891, 19991, 30103, 30203, 30403, 30703, 30803
Offset: 1

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Author

Alvin Hoover Belt, Feb 25 2012

Keywords

Comments

From the Ribenboim book: palindromic primes whose base 10 length is a palindromic prime whose base 10 length is NOT a palindromic prime.

Examples

			11 is a palindromic prime of 2 digits, 2 is a palindromic prime of 1 digit, 1 is NOT a palindromic prime.

References

  • Paulo Ribenboim, The New Book of Prime Number Records, Springer-Verlag New York Inc., 1996, pages 160-161.

Links

Crossrefs

Cf. A002385, A208361 (base-10 length of these numbers), A208363 (palindromic primes with these as the base 10 lengths).

A208363 "3-ply" palindromic primes.

Original entry on oeis.org

10000500001, 10000900001, 10001610001, 10002220001, 10002520001, 10003630001, 10006560001, 10008180001, 10009290001, 10013031001, 10013131001, 10014741001, 10016961001, 10021512001
Offset: 1

Views

Author

Alvin Hoover Belt, Feb 25 2012

Keywords

Comments

From the Ribenboim book: palindromic primes whose length is a palindromic prime whose length is a palindromic prime whose length is NOT a palindromic prime.

Examples

			a(42042) = 99999199999, a(42043) = 10^100 + 3030*10^48 + 1. [_Charles R Greathouse IV_, Feb 26 2012]

References

  • Paulo Ribenboim, The New Book of Prime Number Records, Springer-Verlag New York Inc., 1996, pages 160-161.

Links

Crossrefs

Cf. A002385, A208362 (number of digits of these numbers).

A208361 "1-ply" palindromic primes; see Comments.

Original entry on oeis.org

2, 3, 5, 7, 100030001, 100050001, 100060001, 100111001, 100131001, 100161001, 100404001, 100656001, 100707001, 100767001, 100888001, 100999001, 101030101, 101060101, 101141101, 101171101, 101282101, 101292101, 101343101, 101373101, 101414101, 101424101, 101474101
Offset: 1

Views

Author

Alvin Hoover Belt, Feb 25 2012

Keywords

Comments

From the Ribenboim book: palindromic primes whose length is not a palindromic prime.
a(42046) = 999727999 and a(42047) = 1000008000001. [Charles R Greathouse IV, Feb 26 2012]

Examples

			2 is a palindromic prime of 1 digit, but 1 is not prime, therefore 2 is a 1-ply palindromic prime.
100050001 is a palindromic prime of 9 digits, but 9 is composite, therefore 100050001 is a 1-ply palindromic prime.

References

  • Paulo Ribenboim, The New Book of Prime Number Records, Springer-Verlag New York Inc., 1996, p. 160-161.

Links

Crossrefs

Cf. A109830.

Programs

  • Mathematica
    t = {2, 3, 5, 7}; n = 10000; While[n <= 99999 && Length[t] < 100, n = n + 1; d = IntegerDigits[n]; d2 = FromDigits[Join[d, Rest[Reverse[d]]]]; If[PrimeQ[d2], AppendTo[t, d2]]]; t (* T. D. Noe, Jun 03 2013 *)

Extensions

a(5)-a(26) from Charles R Greathouse IV, Feb 26 2012

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