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Search: id:A035232
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| A035232 |
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Number of substrings of n which are primes. |
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+0
6
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| 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 2, 0, 1, 0, 2, 0, 1, 1, 1, 2, 3, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 3, 1, 1, 0, 1, 1, 2, 0, 1, 0, 2, 0, 0, 1, 1, 2, 3, 1, 2, 1, 2, 1, 2, 0, 1, 1, 1, 0, 1, 0, 2, 0, 0, 1, 2, 2, 3, 1, 2, 1, 2, 1, 2, 0, 0, 1, 2, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 2, 0, 0, 0, 1, 1, 2, 0, 1
(list; graph; listen)
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OFFSET
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1,13
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COMMENT
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No leading 0's allowed in substrings.
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EXAMPLE
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The primes occurring as substrings of 37 are 3, 7, 37, so a(37)=3. a(22)=2, since the prime 2 occurs twice as a substring.
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MATHEMATICA
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a[n_] := Block[{s = IntegerDigits[n], c = 0, d = {}}, l = Length[s]; t = Flatten[ Table[ Take[s, {i, j}], {i, 1, l}, {j, i, l}], 1]; k = l(l + 1)/2; While[k > 0, If[ t[[k]][[1]] != 0, d = Append[d, FromDigits[ t[[k]] ]]]; k-- ]; Count[ PrimeQ[d], True]]; Table[ a[n], {n, 1, 105}]
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CROSSREFS
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Cf. A039997, A039995.
Adjacent sequences: A035229 A035230 A035231 this_sequence A035233 A035234 A035235
Sequence in context: A113686 A039997 A039995 this_sequence A091603 A129688 A086713
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KEYWORD
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base,easy,nonn
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AUTHOR
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Erich Friedman (erich.friedman(AT)stetson.edu)
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EXTENSIONS
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Edited by Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 24 2003
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