A104154 For each natural number n: if the last digit of n is not zero and A004086(n) is prime, append A004086(n) to the sequence.

2, 3, 5, 7, 11, 31, 41, 61, 71, 13, 23, 43, 53, 73, 83, 17, 37, 47, 67, 97, 19, 29, 59, 79, 89, 101, 401, 601, 701, 211, 311, 811, 911, 421, 521, 821, 131, 331, 431, 631, 241, 541, 641, 941, 151, 251, 751, 461, 661, 761, 271, 571, 971, 181, 281, 881

Offset

1,1

Comments

Equivalently, these are the prime numbers ordered by their reversal. - Rémy Sigrist, Feb 13 2022

Links

Rémy Sigrist, Table of n, a(n) for n = 1..9592

Example

The last digit of 13 is not '0' and 31 is prime, therefore we append 31.

Mathematica

a = Select[Range[196], IntegerDigits[ # ][[ -1]] != 0 && PrimeQ[FromDigits[Reverse[ IntegerDigits[ # ]]]] &]; b = {}; For[n = 1, n < Length[a] + 1, n++, AppendTo[b, FromDigits[Reverse[IntegerDigits[a[[n]]]]]]]; b

Prog

(PARI) left(str, n) = { my(v, tmp, x); v =""; tmp = Vec(str); ln=length(tmp); if(n > ln, n=ln); for(x=1, n, v=concat(v, tmp[x]); ); return(v) } \\ Get the left n characters from string str
rev(str) = { local(tmp, s, j); tmp = Vec(Str(str)); s=""; forstep(j=length(tmp), 1, -1, s=concat(s, tmp[j])); return(s) } \\ Get the reverse of the input string
rprime(n) = { local(x, y, v); for(x=1, n, y=rev(x); v=Vec(y); if(left(y, 1)<> "0"&&isprime(eval(y)), print1(y", ")) ) }
(Python)
from itertools import count, islice
from sympy import primerange
def A104154_gen(): # generator of terms
    yield from (int(d[::-1]) for l in count(1) for d in sorted(str(m)[::-1] for m in primerange(10**(l-1), 10**l)))
A104154_list = list(islice(A104154_gen(), 20)) # Chai Wah Wu, Feb 17 2022

Crossrefs

Cf. A004087.

Sequence in context: A157158 A155833 A028867 * A123214 A119834 A095180

Adjacent sequences: A104151 A104152 A104153 * A104155 A104156 A104157

Keyword

nonn,base,look,easy

Author

Cino Hilliard, Mar 09 2005

Extensions

Edited by Stefan Steinerberger, Aug 01 2007

Status

approved