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A028888 Smaller of two successive primes with a palindromic product. 3
2, 7, 17, 191, 1051, 1934063 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

No further terms less than 1.38 * 10^10. - Michael S. Branicky, Feb 07 2021

LINKS

Table of n, a(n) for n=1..6.

Patrick De Geest, More palindromic products of integer sequences

EXAMPLE

17 is in the sequence because 17 * 19 = 323.

19 is not in the sequence because 19 * 23 = 437.

MATHEMATICA

p = 2; t = {}; Do[q = NextPrime[p]; If[Reverse[x = IntegerDigits[p * q]] == x, AppendTo[t, p]]; p = q, {n, 150000}]; t (* Jayanta Basu, Jun 05 2013 *)

Prime[#]&/@Flatten[Position[Times@@@Partition[Prime[Range[1934100]], 2, 1], _?(PalindromeQ[#] &)]] (* Harvey P. Dale, May 14 2019 *)

PROG

(Python)

from sympy import nextprime

def ispal(n): s = str(n); return s == s[::-1]

p, q = 2, 3

while True:

  if ispal(p*q): print(p)

  p, q = q, nextprime(q) # Michael S. Branicky, Feb 07 2021

CROSSREFS

Cf. A028978, A028979.

Sequence in context: A122382 A025554 A285810 * A082627 A160617 A279334

Adjacent sequences:  A028885 A028886 A028887 * A028889 A028890 A028891

KEYWORD

nonn,base,more

AUTHOR

Patrick De Geest

EXTENSIONS

Edited by N. J. A. Sloane, May 04 2007

STATUS

approved

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Last modified October 21 15:46 EDT 2021. Contains 348155 sequences. (Running on oeis4.)