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 1-3 of 3 results.

A051934 a(n) is the smallest palindrome > a(n-1) such that a(1)+a(2)+...+a(n) is a prime.

Original entry on oeis.org

2, 3, 6, 8, 22, 66, 242, 252, 262, 414, 444, 626, 676, 686, 808, 2442, 2552, 2992, 4664, 4884, 6006, 6226, 6666, 8228, 20202, 20302, 20402, 40204, 40304, 60606, 61116, 61716, 80608, 202202, 207702, 212212, 402204, 405504, 609906, 619916, 623326, 801108
Offset: 1

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Author

Felice Russo, Dec 21 1999

Keywords

Comments

a(n) is even except for n = 2. - Chai Wah Wu, Aug 30 2021

Crossrefs

Programs

  • Haskell
    a051934 n = a051934_list !! (n-1)
    a051934_list = f 0 a002113_list where
       f x (m:ms) | a010051 (x + m) == 1 = m : f (x + m) ms
                  | otherwise            = f x ms
    -- Reinhard Zumkeller, Dec 28 2011
  • Mathematica
    palQ[n_] := Reverse[x = IntegerDigits[n]] == x; t = {s = 2}; Do[If[palQ[n] && PrimeQ[x = s + n], AppendTo[t, n]; s = x], {n, 3, 815000}]; t (* Jayanta Basu, Jun 24 2013 *)
    sp[{t_,a_}]:=Module[{k=a+1},While[!PalindromeQ[k]||!PrimeQ[t+k],k++];{t+k,k}]; NestList[ sp,{2,2},50][[;;,2]] (* Harvey P. Dale, Jul 08 2024 *)

Extensions

Missing a(29)=40304 inserted by Reinhard Zumkeller, Dec 28 2011

A087582 Primes such that successive differences are distinct palindromes.

Original entry on oeis.org

2, 3, 5, 11, 19, 23, 67, 89, 311, 523, 937, 1229, 1471, 1559, 1811, 1877, 2281, 2543, 3037, 3319, 3793, 4217, 4651, 5297, 5569, 5801, 6427, 6871, 7477, 8093, 8779, 9587, 10223, 10687, 10889, 11717, 12373, 13049, 13907, 16349, 17167, 17863, 18701
Offset: 0

Views

Author

Amarnath Murthy, Sep 17 2003

Keywords

Comments

Conjecture: Sequence is infinite and every even palindrome is a member.

Examples

			The sequence of successive difference is 1,2,6,8,4,44,22,222,212,414...
		

Crossrefs

Cf. A087581.

Extensions

More terms from David Wasserman, Jun 13 2005

A087583 Distinct primes such that the absolute values of successive differences are distinct palindromes. a(n+1) is chosen to be < a(n) if such a prime exists, minimizing a(n)-a(n+1); otherwise the minimal a(n+1) > a(n) is chosen.

Original entry on oeis.org

2, 3, 5, 11, 7, 29, 37, 103, 59, 271, 19, 107, 349, 127, 359, 157, 419, 137, 409, 701, 277, 691, 257, 661, 197, 641, 167, 773, 97, 733, 239, 1087, 461, 1117, 431, 1097, 643, 1259, 613, 1451, 967, 149, 977, 281, 2393, 61, 919, 41, 929, 31, 839, 3061, 619, 1487
Offset: 0

Views

Author

Amarnath Murthy, Sep 17 2003

Keywords

Comments

The sequence of absolute differences is 1,2,6,4,22,8,66,44.... Conjecture: this sequence is infinite and contains every even palindrome.

Examples

			a(3) = 11: |11-5| = 6, a palindrome. The primes < 5 are excluded because they have already occurred in the sequence. 7 is excluded because |7-5| = 2 has already occurred as a difference.
		

Crossrefs

Extensions

Edited and extended by David Wasserman, Jun 14 2005
Showing 1-3 of 3 results.