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A177275 Primes which are a concatenation of some permutation of the first 5 primes.

%I A177275 #5 Jul 04 2013 11:39:20
%S A177275 112573,115237,115327,211573,235117,257311,327511,352711,357211,
%T A177275 372511,511237,511327,511723,521137,521173,572311,711523,725113,
%U A177275 735211,751123
%N A177275 Primes which are a concatenation of some permutation of the first 5 primes.
%C A177275 There are 20 terms in the sequence. Each is a 6-digit prime with sum of digits equal to 19 = A051351(5).
%C A177275 For each of the 20 entries we define the index i via prime(i) = a(n), which yields the following 20 pairs of (i, A007953(i)):
%C A177275 (10668,21), (10892,20), (10901,11), (18940,22), (20845,19) HP,
%C A177275 (22622,14), (28208,20), (30192,15), (30538,19) HP, (31709,20),
%C A177275 (42386,23), (42392,20), (42426,18), (43145,17), (43149,21),
%C A177275 (47000,11), (57421,19) HP, (58426,25), (59175,27), (60315,15)
%C A177275 Where prime(i) is in A033548, this is marked as "HP" for "Honaker Prime".
%e A177275 a(1) = 11//2//5//7//3 = 112573 = prime(10668).
%e A177275 a(5) = 2//3//5//11//7 = 235117 = prime(20845).
%e A177275 a(20) = 7//5//11//2//3 = 751123 = prime(60315).
%p A177275 catL := proc(L) local a,i,dgs ; a := op(1,L) ; for i from 2 to nops(L) do dgs := max(1, 1+ilog10(op(i,L))) ; a := a*10^dgs+op(i,L) ; end do: a ; end proc:
%p A177275 A177275 := proc() local pL,a,c ; pL := [seq(ithprime(c),c=1..5)] ; a := {} ; for c in combinat[permute](pL) do p := catL(c) ; if isprime(p) then a := a union {p} ; end if; end do: print(sort(a)) ; end proc:
%p A177275 A177275() ; # _R. J. Mathar_, May 09 2010
%Y A177275 Cf. A000040, A033548, A134966, A177061.
%K A177275 nonn,base,fini,full
%O A177275 1,1
%A A177275 Ulrich Krug (leuchtfeuer37(AT)gmx.de), May 06 2010
%E A177275 Added keyword:base,full. Removed the variable p. - _R. J. Mathar_ and _Zak Seidov_, May 09 2010