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A083660 Smallest nonnegative integer m such that fi(n,m)=(n)m(n-1)m(n-2)m...m(2)m(1) is prime. +0
2
1, 5, 14, 5, 5, 9, 1, 1, 29, 23, 28, 13, 46, 22, 18, 116, 35, 18, 155, 7, 81, 1, 139, 52, 262, 215, 56, 29, 11, 6, 256, 119, 381, 592, 67, 189, 116, 46, 5, 275, 139, 27, 101, 118, 96, 167, 196, 393, 275, 91, 146, 415, 193, 127, 85, 73, 6, 4, 50, 118, 1046, 362, 5, 431, 248 (list; graph; listen)
OFFSET

2,2

COMMENT

I conjecture that a(n) for every n greater than 1 exist and is less than n^2. I have defined for each n (n>1), a sequence {fni(m)} of nonnegative integers (probably infinite) such that fni(m) is the m-th nonnegative integer such that fi(n,fni(m)) is prime number. For example : f2i=A032702 f3i: 5,8,11,20,22,23,28,34,37,38,41,43,44,52,53,56,59,71,74,77,79, 82,83,86,88,94,110,128,133,134,137,140,152,154... f4i: 14,15,23,25,37,39,44,54,55,70,79,88,90,98,102,118,123,134,136,143 144,151,174,182,202,209,215,226,230,232,245,254,... f5i: 5,17,20,23,25,28,29,56,58,71,77,109,130,140,154, 160,167,196,206,233,244,245... f6i: 5,8,14,44,70,73,79,80,91,107,121,170,191,209,238, 260,269,280,293,302,308,314,... f7i: 9,15,17,41,52,80,89,92,109,128,152,162,169,176,200, 217,230,251,257,272,280,286,... . . f82i: 1404,1750,1762,1959,2000,... (cf. Prime bylisting www.primepuzzles.net) . . . By this definition a(n)=fni(1) for n>1.

LINKS

C. Rivera, puzzle 8 (www.primepuzzles.net).

EXAMPLE

a(4)=14 because fi(4,14)=4143142141 is prime and fi(4,k) for each k less than 14 is composite.

CROSSREFS

Cf. A032702.

Adjacent sequences: A083657 A083658 A083659 this_sequence A083661 A083662 A083663

Sequence in context: A049506 A069524 A051542 this_sequence A003079 A067113 A101774

KEYWORD

nonn,uned,base

AUTHOR

Farideh Firoozbakht (f.firoozbakht(AT)sci.ui.ac.ir), Jun 14 2003

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Last modified October 9 14:06 EDT 2008. Contains 144831 sequences.


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