|
| |
|
|
A070018
|
|
a(n) = smallest prime p = prime(k) such that gcd( prime(k+1) - prime(k), prime(k+2) - prime(k+1) ) = 2n.
|
|
1
| |
|
|
3, 89, 47, 1823, 1627, 199, 5939, 5591, 15823, 83117, 259033, 16763, 365851, 1074167, 69593, 1625027, 2541289, 255767, 11772613, 3312227, 247099, 3565931
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
FORMULA
| a(n)=Min{x : A057467(x)=2n}.
|
|
|
EXAMPLE
| n=21: a(21)=247099, the consecutive prime triple {247099,247141,247183} determines {42,42} successive differences, the GCD of which is 2n=42.
|
|
|
MATHEMATICA
| f[x_] := GCD[Prime[x+1]-Prime[x], Prime[x+2]-Prime[x+1]]; t = Table[0, {256} ]; Do[ c = f[n]; If[c <257 && t[[b]] == 0, t[[c]] = n], {n, 2, 1000000} ]; t Prime[t]
|
|
|
CROSSREFS
| Cf. A001223, A057467. Different from A054682
Sequence in context: A037112 A093748 A156737 * A054682 A106944 A142252
Adjacent sequences: A070015 A070016 A070017 * A070019 A070020 A070021
|
|
|
KEYWORD
| nonn,more
|
|
|
AUTHOR
| Labos E. (labos(AT)ana.sote.hu) and Benoit Cloitre (benoit7848c(AT)orange.fr), Apr 12 2002
|
| |
|
|
