login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A261493 Palindromes that are concatenation of palindromic prime numbers in increasing order up to the n-th and then in decreasing order. 1
2, 232, 23532, 2357532, 2357117532, 235711101117532, 235711101131101117532, 235711101131151131101117532, 235711101131151181151131101117532, 235711101131151181191181151131101117532, 235711101131151181191313191181151131101117532 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Subsequence of A043037.

LINKS

Table of n, a(n) for n=1..11.

EXAMPLE

For n=6, the first 6 palindromic primes are 2,3,5,7,11,101. Relevant subsequence that produce a(6) is 2,3,5,7,11,101,11,7,5,3,2. Concatenation of items with that order determines a(6) = 235711101117532.

MATHEMATICA

palQ[n_] := Reverse[idn = IntegerDigits@ n] == idn; s = Select[ Prime@ Range@ 1000, palQ]; f[n_] := FromDigits@ Flatten[ IntegerDigits@# & /@ Join[ Take[s, n], Reverse@ Take[s, n - 1]]]; Array[f, 11] (* Robert G. Wilson v, Aug 24 2015 *)

CROSSREFS

Cf. A002385, A048677.

Sequence in context: A113800 A133495 A066622 * A012671 A012526 A012668

Adjacent sequences:  A261490 A261491 A261492 * A261494 A261495 A261496

KEYWORD

nonn,easy,base

AUTHOR

Altug Alkan, Aug 21 2015

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 9 00:32 EST 2019. Contains 329871 sequences. (Running on oeis4.)