A061365 Numbers k such that either k or its reversal (but not both) is prime.

14, 16, 19, 20, 23, 29, 30, 32, 34, 35, 38, 41, 43, 47, 50, 53, 59, 61, 67, 70, 74, 76, 83, 89, 91, 92, 95, 98, 103, 104, 106, 109, 110, 112, 118, 119, 124, 125, 127, 128, 130, 133, 134, 136, 137, 139, 140, 142, 145, 146, 152, 160, 163, 164, 166

Offset

1,1

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Example

14=2*7 is a term as 41 is prime but 14 is not;
13 is not a term as its reversal is also a prime.

Mathematica

Select[ Range[169], Xor[ PrimeQ[ # ], PrimeQ[ FromDigits[ Reverse[ IntegerDigits[ # ]]]]] & ]

Prog

(PARI) { n=0; for (m=0, 3910, x=m; r=0; while (x>0, d=x-10*(x\10); x\=10; r=r*10 + d); if ((isprime(m) + isprime(r)) == 1, write("b061365.txt", n++, " ", m)) ) } \\ Harry J. Smith, Jul 21 2009

Crossrefs

Sequence in context: A177982 A034305 A091898 * A327822 A102107 A217707

Adjacent sequences: A061362 A061363 A061364 * A061366 A061367 A061368

Keyword

nonn,base

Author

Reinhard Zumkeller, May 21 2002

Status

approved