login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A242346 Smaller member of a Sophie Germain pair in which each member of the pair is the smallest of its prime triple (p, (p^3)+2, (p^5)+2). 1
8629739, 77115359, 173508869, 343621919, 419597309, 573556349, 763154039, 770676239, 847344419, 851521949, 951418229, 1014432869, 1252780829, 1260053939, 1322933519, 1529921909, 1569236309, 1861760819, 1954231199, 2048205689, 2071334939, 2583377789, 2658083819 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
a(1): p = 8629739; (2*p)+1 = 17259479
Prime Triplets of the form (p,(p^3)+2,(p^5)+2): (8629739, 642677333350934910421, 47861720360612147562343307996312701 );(17259479, 5141419560476273559241, 1531575495230651978949727458917513401)
PROG
(Python)
p1=2
n=2
count=0
while p1>2:
....## Generate the pair
....cc=[]
....cc.append(p1)
....for i in range(1, n):
........cc.append((2**(i)*p1+((2**i)-1)))
....## chain entries cubed + 2
....cc2=[(c*c*c)+2 for c in cc]
....## chain entries power to 5 + 2
....cc3=[(c**5)+2 for c in cc]
....## check if cc is a Sophie Germain Pair or not
....## pf.isp_list returns True or false for a given list of numbers
....## if they are prime or not
....##
....pcc=pf.isp_list(cc)
....pcc2=pf.isp_list(cc2)
....pcc3=pf.isp_list(cc3)
....## Number of primes for cc, cc2, cc3
....npcc=pcc.count(True)
....npcc2=pcc2.count(True)
....npcc3=pcc3.count(True)
....if npcc==n and npcc2==n and npcc3==n:
........print "For length ", n, " the series is : ", cc, ", ", cc2 , " and ", cc3
....p1=pf.nextp(p1)
CROSSREFS
Sequence in context: A237074 A345616 A346333 * A015378 A337463 A151936
KEYWORD
nonn,hard
AUTHOR
Abhiram R Devesh, May 11 2014
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 12 13:47 EDT 2024. Contains 374247 sequences. (Running on oeis4.)