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A181884 The sums of pairs of adjacent terms are the odd palindromic primes in ascending order. 4

%I #21 Jan 02 2023 12:30:48

%S 3,0,5,2,9,92,39,112,69,122,191,162,211,172,555,202,585,212,707,222,

%T 10079,422,10179,1132,10279,2142,10579,2242,11089,2742,11189,3152,

%U 11589,3862,11689,4372,11989,4572,12089,5382,12589,5592,12889

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

%C This sequence was originally presented at http://www.sanaristikot.net by _V.J. Pohjola_, Nov 11 2010. [Added by _V.J. Pohjola_, Nov 25 2010.]

%C There are four possible solutions: see A181881-A181884.

%H V. J. Pohjola, <a href="http://list.seqfan.eu/oldermail/seqfan/2010-November/006331.html">a(n)+a(n+1) = palindromic prime</a>, Posting to the Sequence Fans Mailing List, Nov 11 2010.

%t lst = {}; a = 3; 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 < nn, Goto[alku1]]; lst (* _V.J. Pohjola_, Nov 25 2010 *)

%t a[1] = 3; pp = Select[Prime[Range[3000]], PalindromeQ]; lp = Length[pp]-1;

%t aa = Table[a[n] + a[n+1], {n, lp}]; Array[a, lp] /. Solve[Thread[aa == Rest[pp]]][[1]] (* _Jean-François Alcover_, Feb 17 2018 *)

%Y Cf. A002385, A181881, A181882, A181883.

%K nonn,easy,base

%O 1,1

%A _N. J. A. Sloane_, Nov 18 2010

%E More terms from _Nathaniel Johnston_, Nov 22 2010

%E Last term corrected by _Jean-François Alcover_, Feb 17 2018

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Last modified April 23 15:20 EDT 2024. Contains 371916 sequences. (Running on oeis4.)