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A171154 Smallest prime whose decimal expansion begins with concatenation of first n primes in descending order. 5
2, 3203, 5323, 75323, 11753221, 131175329, 171311753203, 19171311753229, 231917131175321, 292319171311753231, 3129231917131175327, 3731292319171311753239, 41373129231917131175321 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

(1) Sequence is conjectured to be infinite

(2) a(n) ="p(n)...p(1) R(n)"

(3) R(n) for n>1: "03", 3, 3, 21, 9, "03", 29, 1, 31, 7, 39, 1, 33, 69, 23, 3, 59, 27, ...

(4) It is conjectured that R(n)=1 for infinite many n

REFERENCES

Leonard E. Dickson: History of the Theory of numbers, vol. I, Dover Publications 2005

LINKS

Table of n, a(n) for n=1..13.

EXAMPLE

a(1)=2=prime(1) is the exceptional case, because no R(1)

a(2)=3203=prime(453) = "32 03", R(2)="03"

a(5)=11753221=prime(772902) = "p(5)...p(1) 21", R(5)=21

CROSSREFS

Cf. A000040, A066065, A019518, A089710, A053546

Sequence in context: A158904 A175080 A243649 * A099689 A065671 A094211

Adjacent sequences:  A171151 A171152 A171153 * A171155 A171156 A171157

KEYWORD

nonn,base

AUTHOR

Ulrich Krug (leuchtfeuer37(AT)gmx.de), Dec 04 2009

STATUS

approved

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Last modified April 27 15:06 EDT 2017. Contains 285528 sequences.