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A075177 Indices of additive primes - primes with prime sum-of-digits, see A046704. 6
1, 2, 3, 4, 5, 9, 10, 13, 14, 15, 18, 19, 23, 24, 26, 30, 32, 33, 34, 36, 37, 40, 41, 43, 44, 45, 46, 48, 49, 50, 53, 56, 57, 60, 61, 64, 65, 66, 67, 68, 71, 72, 74, 75, 78, 79, 80, 82, 86, 87, 89, 90, 91, 93, 102, 105, 106, 108, 109, 110, 111, 116, 117, 118, 121, 124, 128 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
There are 107 additive primes among first 200 primes. There are 38455 additive primes among first 100000 primes. Additive primes are in A046704.
LINKS
FORMULA
PrimePi[A046704(n)]
A000040(a(n)) = A046704(n).
EXAMPLE
Prime(10)=29 is additive prime because 2+9=11 is prime.
MATHEMATICA
Map[PrimePi[ # ]&, Select[Prime[Range[200]], PrimeQ[Apply[ Plus, IntegerDigits[ # ]]]&]
Flatten[Position[Prime[Range[150]], _?(PrimeQ[Total[IntegerDigits[#]]]&), {1}, Heads->False]] (* Harvey P. Dale, May 29 2013 *)
PROG
(Haskell)
import Data.List (elemIndices)
a075177 n = a075177_list !! (n-1)
a075177_list = map (+ 1) $
elemIndices 1 $ map (a010051 . a007953) a000040_list
-- Reinhard Zumkeller, Nov 13 2011
CROSSREFS
Cf. A046704.
Sequence in context: A246397 A015837 A262511 * A062096 A360687 A176008
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Sep 06 2002
STATUS
approved

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Last modified March 29 08:13 EDT 2024. Contains 371265 sequences. (Running on oeis4.)