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A078498 Let q(n) be the prime defined in A078497; sequence gives (q(n)-prime(n))/6. 3
1, 1, 1, 2, 1, 2, 2, 1, 2, 4, 1, 1, 2, 3, 1, 2, 1, 3, 4, 3, 5, 2, 1, 1, 5, 4, 4, 3, 5, 2, 3, 2, 1, 6, 5, 1, 2, 3, 7, 5, 5, 7, 2, 10, 5, 8, 1, 2, 5, 2, 1, 1, 2, 7, 1, 2, 9, 4, 4, 7, 6, 6, 3, 5, 6, 3, 1, 7, 5, 1, 5, 6, 5, 4, 3, 2, 5, 2, 2, 4, 3, 4, 3, 14, 3, 4, 4, 2, 9, 2, 7, 9, 8, 7, 4, 13 (list; graph; refs; listen; history; text; internal format)
OFFSET
5,4
LINKS
FORMULA
For n>4 a(n)=( min{p : p>prime(n), p and 2*prime(n)-p are primes} - prime(n) ) / 6.
EXAMPLE
a(6)=1, a(25)=5.
MATHEMATICA
Table[p = Prime[i]; j = 0; While[j++; df = 6*j; ! ((PrimeQ[p + df]) && (PrimeQ[p - df]))]; j, {i, 5, 100}]
CROSSREFS
Sequence in context: A271106 A273673 A140186 * A350700 A178522 A131240
KEYWORD
nonn,easy
AUTHOR
Serhat Sevki Dincer (sevki(AT)ug.bilkent.edu.tr), Nov 27 2002
EXTENSIONS
More terms from Pab Ter (pabrlos(AT)yahoo.com), May 27 2004
STATUS
approved

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Last modified May 19 04:28 EDT 2024. Contains 372666 sequences. (Running on oeis4.)