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A079066
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"Memory" of prime(n): the number of (previous) primes contained as substrings in prime(n).
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17
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0, 0, 0, 0, 0, 1, 1, 0, 2, 1, 1, 2, 0, 1, 1, 2, 1, 0, 1, 1, 2, 1, 1, 0, 1, 0, 1, 1, 0, 3, 2, 3, 4, 2, 0, 1, 2, 1, 2, 4, 3, 0, 1, 2, 3, 1, 2, 3, 2, 2, 3, 3, 2, 2, 3, 2, 1, 3, 2, 1, 3, 3, 2, 3, 3, 4, 2, 3, 3, 1, 3, 3, 3, 4, 4, 2, 2, 3, 0, 0, 2, 1, 3, 2, 2, 2, 0, 2, 1, 1, 2, 3, 1, 0, 0, 2, 1, 2, 4, 2, 3, 2, 2, 1, 3
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,9
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LINKS
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Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
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FORMULA
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A039997(prime(n)) - 1.
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EXAMPLE
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The primes contained as substrings in prime(3) = 113 are 3, 11, 13. Hence a(30) = 3. 113 is the smallest prime with memory = 3.
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MATHEMATICA
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ub = 105; tprime = Table[ToString[Prime[i]], {i, 1, ub}]; a = {}; For[i = 1, i <= ub, i++, m = 0; For[j = 1, j < i, j++, If[Length[StringPosition[tprime[[i]], tprime[[j]]]] > 0, m = m + 1]]; a = Append[a, m]]; a
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PROG
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(Haskell)
import Data.List (isInfixOf)
a079066 n =
length $ filter (`isInfixOf` (primesDec !! n)) $ take n primesDec
primesDec = "_" : map show a000040_list
-- Reinhard Zumkeller, Jul 19 2011
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CROSSREFS
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Cf. A079075, A035232.
Cf. A033274, A179909, A179910, A179911, A179912, A179913, A179914, A179915, A179916, A179917, A179918, A179919, A179922.
Sequence in context: A025925 A240857 A109066 * A157188 A173266 A224326
Adjacent sequences: A079063 A079064 A079065 * A079067 A079068 A079069
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KEYWORD
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base,easy,nonn
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AUTHOR
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Joseph L. Pe, Feb 02 2003
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EXTENSIONS
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Edited by Robert G. Wilson v, Feb 25 2003
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STATUS
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approved
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