login
Lesser of twin primes, written in base 6.
2

%I #9 Feb 11 2019 01:25:30

%S 3,5,15,25,45,105,135,155,245,255,345,405,455,515,525,1015,1035,1125,

%T 1145,1235,1335,1535,1555,2045,2225,2345,2435,2505,2545,3015,3425,

%U 3445,3455,3545,4025,4415,4435,4505,4525,5015,5155,5405,5525,5545,10005,10035

%N Lesser of twin primes, written in base 6.

%C All but the first value is of the form 6n-1, hence in base 6 end with the digit 5.

%H Nathaniel Johnston, <a href="/A166479/b166479.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A007092(A001359(n)).

%p A001359 := proc(n) option remember: local p: if(n=1)then return 3: fi: p:=procname(n-1): do p:=nextprime(p): if(isprime(p+2))then return p: fi: od: end: A166479 := proc(n) local l: l:=convert(A001359(n),base,6): return op(convert(l,base,10,10^nops(l))): end: seq(A166479(n),n=1..60); # _Nathaniel Johnston_, May 06 2011

%t FromDigits[IntegerDigits[#,6]]&/@Transpose[Select[Partition[ Prime[ Range[ 300]],2,1],#[[2]]-#[[1]]==2&]][[1]] (* _Harvey P. Dale_, Aug 19 2015 *)

%Y Cf. A001359, A007092.

%K base,easy,nonn

%O 1,1

%A _Jonathan Vos Post_, Oct 14 2009

%E Extended by _Nathaniel Johnston_, May 06 2011