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A052078 Smallest prime formed by concatenating n consecutive decreasing numbers, 0 if no such prime exists. 3
2, 43, 0, 10987, 76543, 0, 73727170696867, 4645444342414039, 0, 56555453525150494847, 219218217216215214213212211210209, 0, 25242322212019181716151413, 6059585756555453525150494847, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Starting numbers in concatenations are given by A052080.

If n is divisible by 3, a(n)=0. - Harvey P. Dale, Jun 03 2019

LINKS

Table of n, a(n) for n=1..15.

C. Rivera, Prime Puzzle 78

MATHEMATICA

Table[Min[Select[FromDigits[Flatten[IntegerDigits[#]]]&/@ Partition[ Range[ 1000, 1, -1], n, 1], PrimeQ]], {n, 20}]/.\[Infinity]->0 (* Harvey P. Dale, Jun 03 2019 *)

CROSSREFS

Cf. A052077, A052079, A052080.

Sequence in context: A039622 A130506 A273399 * A069544 A256285 A268467

Adjacent sequences:  A052075 A052076 A052077 * A052079 A052080 A052081

KEYWORD

nonn,base,nice

AUTHOR

Patrick De Geest, Jan 15 2000

EXTENSIONS

Terms for n>6 calculated by Carlos Rivera and Felice Russo

STATUS

approved

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Last modified August 3 05:55 EDT 2020. Contains 336197 sequences. (Running on oeis4.)