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A101215 Numbers n such that concatenation of n with 54321 is a prime. 1
1, 10, 13, 28, 31, 37, 40, 44, 49, 55, 59, 68, 71, 77, 89, 94, 97, 100, 104, 115, 119, 121, 139, 140, 142, 145, 148, 161, 166, 178, 181, 191, 196, 199, 205, 226, 232, 233, 238, 241, 248, 251, 259, 260, 262, 272, 274, 290, 293, 295, 301, 313, 314, 317, 329, 331 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Conjecture 1 : for any integer N ending in 1 or 3 or 7 or 9 there is an infinite sequence of numbers n such that the concatenation nN is a prime. Conjecture 2 : for any integer N there is an infinite sequence of numbers n such that the concatenation Nn is a prime

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

154321,1354321,2854321,3154321 ......... are primes

MATHEMATICA

Select[Range[400], PrimeQ[FromDigits[Join[IntegerDigits[#], {5, 4, 3, 2, 1}]]]&] (* Harvey P. Dale, Sep 28 2013 *)

CROSSREFS

Sequence in context: A074346 A126973 A220045 * A102249 A195313 A219829

Adjacent sequences:  A101212 A101213 A101214 * A101216 A101217 A101218

KEYWORD

nonn,base

AUTHOR

Pierre CAMI, Dec 14 2004

EXTENSIONS

Inserted 10, 40, 100, 260 - R. J. Mathar, Nov 13 2009

STATUS

approved

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Last modified December 12 00:07 EST 2018. Contains 318052 sequences. (Running on oeis4.)