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

Author

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

Keywords

• base
• nonn

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

Examples

			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).
		

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

Crossrefs

Cf. A002385, A007500, A083185, A155214.

Programs

Mathematica

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