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Search: id:A077715
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| A077715 |
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a(1) = 7, a(n) = the smallest prime such that deleting the most significant digit gives a(n-1). If no such number exists then the smallest prime so that a(n-1) is obtained by deleting the two most significant digits. (In general by deleting as many minimum number of (most significant) digits required). |
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+0
4
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| 7, 17, 317, 6317, 26317, 126317, 2126317, 72126317, 372126317, 5372126317, 305372126317, 9305372126317, 409305372126317, 20409305372126317, 100020409305372126317, 9100020409305372126317, 209100020409305372126317
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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a(n) is obtained by prefixing a(n-1) with a number of the form d*10^k where d is a single digit. 0< d < 10. Conjecture: There exists a number k however large for every term. i.e. Only one digit (MSD) need be deleted. In other words For every prime p there exists a prime q such that q = p + d*10^m where 0<d<10. Here m = k + number of digits in a(n-1).
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CROSSREFS
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Cf. A053584, A077713, A077714, A077716.
Sequence in context: A092240 A110120 A053584 this_sequence A089563 A102266 A113765
Adjacent sequences: A077712 A077713 A077714 this_sequence A077716 A077717 A077718
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KEYWORD
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base,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Nov 19 2002
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EXTENSIONS
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More terms from Ray Chandler (rayjchandler(AT)sbcglobal.net), Jul 23 2003
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