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A175546 Primes p such that sod(p)=2*sod(nextprime(p)). 0
19, 37, 59, 109, 127, 149, 239, 307, 419, 691, 1009, 1049, 1229, 1319, 2129, 2309, 2477, 3119, 4019, 5009, 6091, 8093, 8297, 9199, 10139, 10799, 11093, 12007, 12391, 13499, 14009, 14489, 15091, 15497, 18397, 20297, 20899, 21799, 22109, 23599 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

sod(19)=10=2*sod(23)=2*5

sod(59)=14=2*sod(61)=2*7

sod(691)=16=2*sod(701)=2*8

sod(2477)=20=2*sod(2503)=2*10

sod(8297)=26=2*sod(8311)=2*13

sod(9199)=28=2*sod(9203)=2*14

sod(25799)=32=2*sod(25801)=2*16

sod(63997)=34=2*sod(64007)=2*17

sod(98999)=44=2*sod(99013)=2*22

sod(568999)=46=2*sod(569003)=2*23

sod(788999)=50=2*sod(789001)=2*25

sod(4779997)=52=2*sod(4780007)=2*26

sod(7979969)=56=2*sod(7980013)=2*28

sod(29899993)=58=2*sod(29900009)=2*29

sod(27989999)=62=2*sod(27990031)=2*31.

LINKS

Table of n, a(n) for n=1..40.

Zak Seidov, Sod(p)=2*sod(nextprime(p))

MATHEMATICA

Reap[Do[If[(t1=Total[IntegerDigits[(p1=Prime[n])]])==2*(t2=Total[IntegerDigits[(p2=Prime[n+1])]]), Sow[{p1, p2, t1, t2}]], {n, 2000000}]][[2, 1]]

CROSSREFS

A007953 Digital sum (sum of digits, sod).

Sequence in context: A225863 A161705 A131600 * A162471 A124268 A259648

Adjacent sequences:  A175543 A175544 A175545 * A175547 A175548 A175549

KEYWORD

base,nonn

AUTHOR

Zak Seidov, Jun 24 2010

STATUS

approved

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Last modified March 20 19:57 EDT 2019. Contains 321349 sequences. (Running on oeis4.)