[go: up one dir, main page]

login
A082979
Lexicographically earliest rearrangement of primes such that the sum of two consecutive terms is a palindrome.
2
2, 3, 5, 17, 71, 131, 101, 151, 61, 181, 31, 13, 53, 149, 73, 139, 83, 179, 23, 43, 199, 457, 7, 37, 29, 59, 163, 79, 173, 89, 113, 109, 103, 311, 547, 271, 11, 191, 41, 47, 19, 193, 211, 223, 241, 233, 251, 557, 281, 577, 5869, 137, 277, 127, 307, 97, 317, 107
OFFSET
1,1
LINKS
MATHEMATICA
seq={2}; Do[k=3; While[MemberQ[seq, k] || !PalindromeQ[k+seq[[-1]]], k = NextPrime[k]]; AppendTo[seq, k], {i, 1, 50}]; seq (* Amiram Eldar, Dec 04 2018 *)
PROG
(PARI)
ispal(n)={my(v=digits(n)); for(i=1, #v\2, if(v[i]<>v[#v+1-i], return(0))); 1}
seq(n)={my(v=vector(n), M=Map(), t=0); for(n=1, n, forprime(p=1, oo, if(!mapisdefined(M, p) && ispal(p+t), t=p; break)); mapput(M, t, 1); v[n]=t); v} \\ Andrew Howroyd, Dec 04 2018
CROSSREFS
Sequence in context: A173236 A268209 A245641 * A065952 A308316 A089983
KEYWORD
base,nonn,look
AUTHOR
Jason Earls, May 28 2003
STATUS
approved