A177678 Palindromic primes p = q//r//q such that q and r are also palindromic primes.

353, 373, 727, 757, 11311, 31013, 31513, 33533, 37273, 37573, 39293, 71317, 71917, 77977, 1175711, 1178711, 1317131, 1513151, 1917191, 3103013, 3106013, 3127213, 3135313, 3155513, 3160613, 3166613, 3181813, 3193913, 3198913, 3304033

Offset

1,1

Comments

p = palprime(i), q = palprime(j), r = palprime(k) (see A002385).

Indices (i,j,k): (12,2,3), (13,2,4), (15,4,1), (16,4,3), (24,5,2), (52,2,6), (53,2,8), (56,2,12), (65,2,15), (66,2,16), (70,2,20), (74,4,7), (75,4,10), (88,4,18), (140,11,16), (142,11,17), (174,7,4), (206,8,2), (282,10,4), (318,2,21), (319,2,23), (320,2,27), (321,11,3), (323,2,35), (325,2,36), (326,2,39), (327,2,42), (329,2,44), (331,2,45), (354,2,49), (356,2,50), (357,2,52), (358,2,53), (365,2,61), (366,2,63), (368,2,64), (370,2,67), (372,2,70), (424,2,76), (426,2,79), (430,2,84), (434,2,86), (435,2,87), (437,2,89), (439,2,92), (440,2,94), (464,2,97), (467,2,102), (468,2,103), (469,2,107).

Note an example that the description with q and r is not (necessarily) unique: (2388,2,179) or (2388,11,14) for 313383313 = 3//1338331//3 = 313//383//313.

References

M. Gardner: Mathematischer Zirkus, Ullstein Berlin-Frankfurt/Main-Wien, 1988

K. G. Kroeber: Ein Esel lese nie. Mathematik der Palindrome, Rowohlt Tb., Hamburg, 2003

Links

Table of n, a(n) for n=1..30.

Example

3 = palprime(2), 5 = palprime(3), 3//5//3 = 353 = palprime(12) is first term.
3 = palprime(2), 7 = palprime(4), 3//7//3 = 373 = palprime(13) is 2nd term.

Crossrefs

Cf. A002385, A176465.

Sequence in context: A145023 A343714 A343715 * A058375 A059635 A003294

Adjacent sequences: A177675 A177676 A177677 * A177679 A177680 A177681

Keyword

nonn,base

Author

Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), May 10 2010

Status

approved