login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A118507 Larger of two consecutive Sophie Germain primes with the same digital sum. 0
131, 509, 719, 761, 2693, 3593, 3821, 4019, 4073, 4391, 4409, 4481, 4733, 5171, 6131, 6263, 6581, 6761, 7121, 7541, 7841, 9473, 9629, 10163, 10253, 10271, 10331, 10709, 11831, 12653, 12671, 13229, 13553, 14081, 14153, 14249, 14321, 15773, 15791, 16253, 17291 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..41.

EXAMPLE

113 and 131 are consecutive Sophie Germain primes that have the same digital sum, hence 131 is in the sequence. - Michel Marcus, Dec 01 2013

PROG

(PARI) lista(nn) = {lastsd = 0; forprime(p=2, nn, if (isprime(2*p+1), digs = digits(p); sd = sum(i=1, #digs, digs[i]); if (sd == lastsd, print1(p, ", ")); lastsd = sd; ); ); } \\ Michel Marcus, Dec 01 2013

CROSSREFS

Cf. A005384.

Sequence in context: A068680 A276255 A142555 * A105837 A142205 A142807

Adjacent sequences:  A118504 A118505 A118506 * A118508 A118509 A118510

KEYWORD

base,nonn

AUTHOR

Luc Stevens (lms022(AT)yahoo.com), May 06 2006

EXTENSIONS

Missing term 6761 and more terms added by Michel Marcus, Dec 01 2013

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 24 06:53 EDT 2019. Contains 323529 sequences. (Running on oeis4.)