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A117458 Primes and their indices such that when their respective SOD's are both prime, the SOD of the index is the nextprime of the prime SOD. 5
227, 313, 1723, 2003, 2311, 2609, 3329, 3701, 4007, 4027, 4801, 4931, 5107, 7253, 10457, 12143, 12163, 12211, 12433, 12547, 13063, 14143, 14341, 14831, 15139, 15373, 16091, 17027, 17047, 19403, 20047, 20261, 21059, 21149, 22157, 23053 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

"SOD" = "sum of digits".

LINKS

Table of n, a(n) for n=0..35.

FORMULA

Individually sum the digits of both prime index and associated prime. If both sums are prime and the sum of the index is the next prime of the prime SOD, add to sequence.

EXAMPLE

In a(1) = 313, the number 65 is the index of the prime 313. The SOD(i) = 11. The SOD(p) = 7. 11 is the next prime after 7.

CROSSREFS

Cf. A117459-A117463.

Sequence in context: A179141 A259059 A142261 * A252026 A210513 A142842

Adjacent sequences:  A117455 A117456 A117457 * A117459 A117460 A117461

KEYWORD

easy,nonn,base

AUTHOR

Enoch Haga, Mar 18 2006

STATUS

approved

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Last modified November 21 07:22 EST 2019. Contains 329350 sequences. (Running on oeis4.)