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A062220
Numbers k such that the smoothly undulating palindromic number (38*10^k - 83)/99 is a prime.
1
3, 9, 15, 17, 21, 57, 4233, 4335, 13221, 26447, 29897, 91997
OFFSET
1,1
COMMENTS
Prime versus probable prime status and proofs are given in the author's table.
No further terms < 100000. - Ray Chandler, Aug 17 2011
EXAMPLE
k=21 -> (38*10^21 - 83)/99 = 383838383838383838383.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Patrick De Geest and Hans Rosenthal (Hans.Rosenthal(AT)t-online.de), Jun 15 2001
EXTENSIONS
a(12)=91997 from Ray Chandler, Jul 29 2011
Edited by Ray Chandler, Aug 17 2011
STATUS
approved