|
| |
|
|
A138254
|
|
Balanced prime numbers n such that n*(n-1)-1 is a balanced prime.
|
|
0
| |
|
|
10657, 15161, 422911, 691709, 735877, 816239, 1025267, 1030511, 1471891, 1618937, 1683497, 2125411, 2322367, 2448961, 2776157, 2856461, 2880949, 3027319, 3091409, 3114509, 3183337, 3642479, 3797539, 3858091, 3894181, 4752031, 5383387, 5832467, 6052927, 6077821
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
EXAMPLE
| 10657 is balanced prime, 10657*10656-1=113560991 is balanced prime
(113560973(prev)+113561009(next))/2=113560991
|
|
|
MATHEMATICA
| NextPrime[n_Int]:=Module[{k}, k=n+1; While[ !PrimeQ[k], k++ ]; k]; PrevPrime[n_Int]:=Module[{k}, k=n-1; While[ !PrimeQ[k], k-- ]; k]; s=""; For[i=2, i< 10^5, p=Prime[i]; If[(Prime[i-1]+Prime[i+1])/2==p, r=p*(p-1)-1; a=PrevPrime[r]; b=NextPrime[r]; If[PrimeQ[r]&&r==(a+b)/2, (*Print[p, ":", a, ", ", b, "; ", r]*)s=s<>ToString[p]<>", "]]; i++ ]; Print[s]
|
|
|
CROSSREFS
| Cf. A006562.
Sequence in context: A009421 A013817 A013904 * A154510 A157326 A006006
Adjacent sequences: A138251 A138252 A138253 * A138255 A138256 A138257
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Vladimir Orlovsky (4vladimir(AT)gmail.com), May 05 2008
|
|
|
EXTENSIONS
| a(9)-a(30) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Aug 24 2011
|
| |
|
|
