A174884 Palindromic primes using only (decimal) square digits 0,1,4,9.

11, 101, 191, 919, 11411, 19991, 91019, 94049, 94949, 1114111, 1190911, 1409041, 1411141, 1444441, 1490941, 1909091, 1941491, 9049409, 9091909, 9109019, 9110119, 9149419, 9199919, 9400049, 9414149, 9419149, 9440449, 9919199

Offset

1,1

Comments

Four decimal square digits: 0 = 0^2, 1 = 1^2, 4 = 2^2, 9 = 3^2

With the exception of 11 all palindromic primes have an odd number of digits

References

Roland Sprague, Unterhaltsame Mathematik, neue Probleme, ueberraschende Loesungen, Vieweg, Braunschweig, 1961

David Wells, The Penguin Dictionary of Curious and Interesting Numbers, Penguin Books: London, 1986.

Links

Chai Wah Wu, Table of n, a(n) for n = 1..10000

Example

11 = prime(5) = palprime(5), 1st term of sequence.
101 = prime(26) = palprime(6), 2nd term of sequence.
Next term using only 0 and 1 is 100111001 = prime(5767473) = palprime(785).

Mathematica

Select[FromDigits/@Tuples[{0, 1, 4, 9}, 7], PalindromeQ[#]&&PrimeQ[#]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 06 2019 *)

Crossrefs

Cf. A002385, A007500, A083185, A155214.

Sequence in context: A180404 A142317 A180406 * A121402 A156307 A057532

Adjacent sequences: A174881 A174882 A174883 * A174885 A174886 A174887

Keyword

base,nonn

Author

Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Apr 01 2010

Status

approved