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A326442
Emirp-indexed emirps: emirps with emirp subscripts.
1
157, 991, 1217, 7057, 7523, 7649, 7841, 9293, 9661, 9833, 9923, 10009, 10079, 10457, 10487, 11447, 11927, 12301, 12547, 12763, 13469, 13513, 13693, 14177, 15511, 15683, 30557, 31033, 31069, 31267, 31277, 32299, 32341, 32911, 33029, 35363, 35801, 72559, 73453
OFFSET
1,1
COMMENTS
Here the 'subscript' of an emirp is the index of it over all the primes, not over the emirps (otherwise we would get {A006567(A006567(n))} sorted). - Jianing Song, Oct 29 2019
LINKS
Chris K. Caldwell and G. L. Honaker, Jr., Prime curio for 157
EXAMPLE
157 is a term because 157, 751, pi(157) = 37 and 73 are all primes.
MATHEMATICA
Do[y=IntegerReverse; z=PrimeQ; k=PrimePi[n]; a=y[n]; b=y[k]; If[!a==n&&!b==k&&z[a]&&z[b]&&z[n]&&z[k], Print[n]], {n, 1, 10^5}]
PROG
(PARI) is_emirps(n) = my(r=eval(concat(Vecrev(Str(n))))); isprime(r)&&r!=n&&isprime(n); \\ A006567
isok(n) = is_emirps(n) && is_emirps(primepi(n)); \\ Michel Marcus, Oct 14 2019
CROSSREFS
Sequence in context: A226972 A337427 A142766 * A258436 A167992 A038493
KEYWORD
nonn,base
AUTHOR
Metin Sariyar, Oct 09 2019
STATUS
approved