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A131645 Beastly primes (primes containing 666 as a substring). +0
3
6661, 16661, 26669, 46663, 56663, 66601, 66617, 66629, 66643, 66653, 66683, 66697, 76667, 96661, 96667, 106661, 106663, 106669, 116663, 146669, 166601, 166603, 166609, 166613, 166619, 166627, 166631, 166643, 166657, 166667, 166669, 166679 (list; graph; listen)
OFFSET

1,1

COMMENT

Asymptotic density n/log(n), since almost all primes are of this form.

LINKS

Charles R Greathouse IV and Harry J. Smith, Table of n, a(n) for n=1..20000

MATHEMATICA

Select[Range[300000], StringFreeQ[ToString[ # ], "666"] == False && PrimeQ[ # ] &]

Select[Prime[Range[300000]], !StringFreeQ[ToString[ # ], "666"]&] - from Zak Seidov, Jan 09 2009

PROGRAM

(PARI) digitsIn(x) = 1 + log(x)\log(10) { allocatemem(932245000); default(primelimit, 4294965247); m=1; forprime (p=6660, 68466670, d=digitsIn(p); for (i=1, d-3, t=10^i; u=p\t; x=u-(u\1000)*1000; if (x==666, print(m, " ", p); write("b131645.txt", m, " ", p); m=m+1; break; ); ) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jan 11 2009]

CROSSREFS

Sequence in context: A043634 A060792 A119519 this_sequence A015310 A043516 A046410

Adjacent sequences: A131642 A131643 A131644 this_sequence A131646 A131647 A131648

KEYWORD

base,nonn

AUTHOR

Tanya Khovanova (tanyakh(AT)yahoo.com), Sep 08 2007

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Last modified December 19 12:50 EST 2009. Contains 171053 sequences.


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