A345472 - OEIS

A345472

Emirps p such that both p and its reversal are sums of three consecutive primes.

1151, 1249, 1511, 3467, 3697, 7643, 7963, 9421, 11593, 32749, 36467, 39511, 71329, 76463, 92317, 94723, 110119, 111109, 123707, 124309, 124823, 128377, 141371, 146953, 150383, 155153, 160159, 164291, 167779, 173141, 178223, 184609, 190807, 192383, 192461, 199247, 304193, 304879, 306133, 322871

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OFFSET

1,1

COMMENTS

Numbers p such that p and its digit reversal are distinct members of A034962.

LINKS

Robert Israel, Table of n, a(n) for n = 1..1792

EXAMPLE

a(4) = 1511 because 1511 and its reversal 1151 are distinct primes, and 1511 = 499+503+509 and 1151 = 379+383+389 are sums of three consecutive primes.

MAPLE

digrev:= proc(n) local L, i;

L:= convert(n, base, 10);

add(L[-i]*10^(i-1), i=1..nops(L))

end proc:P:= select(isprime, [2, seq(i, i=3..nextprime(nextprime(333333)), 2)]):

P3:= convert(select(isprime, P[1..-3]+P[2..-2]+P[3..-1]), set):

B:= P3 intersect map(digrev, P3):

sort(convert(remove(t -> digrev(t)=t, B), list);

CROSSREFS

Cf. A006567, A034962.

Sequence in context: A329520 A054999 A086259 * A175606 A179036 A179037

Adjacent sequences: A345469 A345470 A345471 * A345473 A345474 A345475

KEYWORD

nonn,base

AUTHOR

J. M. Bergot and Robert Israel, Jun 20 2021

STATUS

approved