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Search: id:A120094
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| A120094 |
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Rows of Pascal's triangle which contain no terms numerically adjacent to odd primes (the 1's at either end are of course numerically adjacent to the even prime 2). |
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+0
1
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OFFSET
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0,1
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COMMENT
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Apart from the (2^i-1)-th rows, there are no obvious divisibility properties that would explain the coincidence. '1' is the 0-th row.
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EXAMPLE
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The 7th, 15th, 31st, ... (2^i-1)-th rows are all included as pascal's triangle only contains odd terms, thus all numerically adjacent terms are even.
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PROGRAM
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(PARI) for(n=2, 1000, for(k=1, n\2, ok=1; c=n!/k!/(n-k)!; if(ispseudoprime(c+1)||ispseudoprime(c-1), ok=0; break; )); if(ok, print(n)))
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CROSSREFS
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Adjacent sequences: A120091 A120092 A120093 this_sequence A120095 A120096 A120097
Sequence in context: A139597 A117747 A137196 this_sequence A078485 A014001 A063592
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KEYWORD
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nonn
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AUTHOR
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Phil Carmody (pc+oeis(AT)asdf.org), Aug 15 2006
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