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 A224827 Primes p such that prime(floor(p/10) + (p mod 10)) = p. 1
 64279, 64319, 64483, 64513, 64621 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Subset of A224843. Sequence is clearly finite, since the ratio prime(n)/n is unbounded. By comparing prime(x/10) with x and using suitable functions which provide upper and lower bounds for prime(x), it is also possible to infer that no more terms exist. - Giovanni Resta, Jul 22 2013 LINKS Table of n, a(n) for n=1..5. Chris K. Caldwell and G. L. Honaker, Jr., Prime Curios! 64621 EXAMPLE prime(6462+1) = 64621 which is prime. Hence, 64621 is in sequence. MAPLE with(numtheory):KD := proc(p) ithprime((p-(p mod 10))/10 + (p mod 10))=p ; end proc: for p from 1 to 65000 do if KD(p) then printf("%d, ", p) ; end if; end do:# K. D. Bajpai, Jul 21 2013 with(numtheory):K:=proc()local n, a, c, p; p:=3; c:=1; for n from 1 to 50000 do; p:=ithprime(n); a:= ithprime((p-(p mod 10))/10 + (p mod 10)); if p=a then lprint(c, p); c:=c+1; fi; od; end: K(); # K. D. Bajpai, Jul 21 2013 PROG (PARI) is(p)=p==prime(p\10+p%10)&&isprime(p) \\ Charles R Greathouse IV, Jul 22 2013 CROSSREFS Cf. A224843. Sequence in context: A031859 A182811 A236702 * A234128 A205631 A205333 Adjacent sequences: A224824 A224825 A224826 * A224828 A224829 A224830 KEYWORD nonn,base,fini,full AUTHOR K. D. Bajpai, Jul 21 2013 STATUS approved

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Last modified October 1 04:50 EDT 2023. Contains 365812 sequences. (Running on oeis4.)