A181881 The sums of pairs of adjacent terms are the odd palindromic primes in ascending order.

1, 2, 3, 4, 7, 94, 37, 114, 67, 124, 189, 164, 209, 174, 553, 204, 583, 214, 705, 224, 10077, 424, 10177, 1134, 10277, 2144, 10577, 2244, 11087, 2744, 11187, 3154, 11587, 3864, 11687, 4374, 11987, 4574, 12087, 5384, 12587, 5594, 12887, 6504, 13387

Offset

1,2

Comments

This sequence was originally presented at http://www.sanaristikot.net by Jaakko Himberg (jaska.himberg(AT)suomiforum.com), Nov 06 2010. [Added by V.J. Pohjola, Nov 25 2010.]

There are four possible solutions: see A181881-A181884.

Links

V. J. Pohjola, Table of n, a(n) for n = 1..113

V. J. Pohjola, a(n)+a(n+1) = palindromic prime, Posting to the Sequence Fans Mailing List, Nov 11 2010.

Mathematica

lst = {}; a = 1; c = 1; Label[alku1]; b = c; Label[alku2]; b =b + 1; If[PrimeQ[a + b] && IntegerDigits[a + b] == Reverse[IntegerDigits[a + b]], AppendTo[lst, a], Goto[alku2]]; c = a; a = b; If[a < 100000, Goto[alku1]]; lst (* V.J. Pohjola, Nov 22 2010 *)
a[1] = 1; pp = Select[Prime[Range[3000]], PalindromeQ]; lp = Length[pp]-1; aa = Table[a[n] + a[n+1], {n, lp}]; Array[a, lp] /. Solve[Thread[aa == Rest[pp]]][[1]] (* Jean-François Alcover, Feb 17 2018 *)

Crossrefs

Cf. A002385, A181882, A181883, A181884.

Sequence in context: A127074 A328322 A109617 * A071373 A229597 A366656

Adjacent sequences: A181878 A181879 A181880 * A181882 A181883 A181884

Keyword

nonn,easy,base

Author

N. J. A. Sloane, Nov 18 2010

Extensions

More terms from V.J. Pohjola, Nov 22 2010

Status

approved