A030469
Primes which are concatenations of three consecutive primes.
Original entry on oeis.org
5711, 111317, 171923, 313741, 414347, 8997101, 229233239, 239241251, 263269271, 307311313, 313317331, 317331337, 353359367, 359367373, 383389397, 389397401, 401409419, 409419421, 439443449, 449457461
Offset: 1
(1) 5=p(3), 7=p(4), 11=p(5) gives a(1).
(2) 7=p(4), 11=p(5), 13=p(6), but 71113 = 7 x 10159
- Richard E. Crandall, Carl Pomerance: Prime Numbers, Springer 2005 - from Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Nov 09 2009
- John Derbyshire: Prime obsession, Joseph Henry Press, Washington, DC 2003 - from Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Nov 09 2009
- Marcus du Sautoy: Die Musik der Primzahlen. Auf den Spuren des groessten Raetsels der Mathematik, Beck, Muenchen 2004
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Select[Table[FromDigits[Flatten[IntegerDigits/@{Prime[n],Prime[n+1],Prime[n+2]}]],{n,11000}],PrimeQ] (* Zak Seidov, Oct 16 2009 *)
concat[{a_,b_,c_}]:=FromDigits[Flatten[IntegerDigits/@{a,b,c}]]; Select[ concat/@ Partition[ Prime[ Range[200]],3,1],PrimeQ] (* Harvey P. Dale, Sep 06 2017 *)
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for(i=1,999, isprime(p=eval(Str(prime(i),prime(i+1),prime(i+2)))) & print1(p," ")) \\ M. F. Hasler, Nov 10 2009
A383114
Triprimes that are concatenations of three consecutive primes.
Original entry on oeis.org
357, 131719, 434753, 475359, 717379, 97101103, 101103107, 103107109, 109113127, 139149151, 151157163, 157163167, 163167173, 167173179, 173179181, 193197199, 197199211, 199211223, 227229233, 241251257, 281283293, 293307311, 331337347, 347349353, 367373379, 397401409, 461463467, 487491499
Offset: 1
a(3) = 434753 is a term because it is the concatenation of the consecutive primes 43, 47 and 53 and 434753 = 11^2 * 3593 is the product of three primes, counted with multiplicity.
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cat3:= proc(a,b,c)
(a*10^(1+ilog10(b))+b)*10^(1+ilog10(c))+c
end proc:
select(t ->numtheory:-bigomega(t)=3, [seq(cat3(ithprime(i),ithprime(i+1),ithprime(i+2)),i=1..100)]);
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p3[p_]:=FromDigits[Join[IntegerDigits[Prime[p]],IntegerDigits[Prime[p+1]],IntegerDigits[Prime[p+2]]]];Select[Array[p3,100],PrimeOmega[#]==3&] (* James C. McMahon, Jun 09 2025 *)
A167517
Emirps (A007500) which are concatenation of three consecutive primes (A030469).
Original entry on oeis.org
353359367, 193319491951, 334733593361, 344934573461, 346734693491, 732173317333, 902990419043, 104591046310477, 133091331313327, 141591417314177, 146571466914683, 150131501715031, 154431545115461
Offset: 1
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for(i=1,9999, isprime(eval(p=Str(prime(i),prime(i+1),prime(i+2)))) & isprime(eval(concat(vecextract(Vec(p),"-1..1"))))& print1(p,", "))
A244007
Semiprimes which are concatenation of three consecutive primes.
Original entry on oeis.org
235, 71113, 192329, 232931, 293137, 535961, 616771, 677173, 737983, 798389, 838997, 107109113, 137139149, 149151157, 181191193, 191193197, 211223227, 223227229, 233239241, 257263269, 269271277, 277281283, 337347349, 349353359, 373379383, 421431433, 431433439
Offset: 1
235 is in the sequence because concatenation of [2, 3, 5] = 235 = 5 * 47, which is semiprime.
71113 is in the sequence because concatenation of [7, 11, 13] = 71113 = 7 * 10159, which is semiprime.
111317 is not in the sequence because, though 111317 is concatenation of three consecutive primes [11, 13, 17], but it is not semiprime.
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with(numtheory): with(StringTools): A244007:= proc() local a,b,c,k,m; a:=ithprime(n); b:=ithprime(n+1); c:=ithprime(n+2);m:=parse(cat(a,b,c)); k:=bigomega(m); if (k)=2 then RETURN (m); fi; end: seq(A244007 (), n=1..100);
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A244007 = {}; Do[t = FromDigits[Flatten[IntegerDigits /@ {Prime[n], Prime[n + 1], Prime[n + 2]}]]; If [PrimeOmega[t] == 2, AppendTo[A244007, t]], {n, 100}]; A244007
A244163
Primes which are the concatenation of three consecutive primes p, q, r while the sum (p + q + r) yields another prime.
Original entry on oeis.org
5711, 111317, 171923, 313741, 414347, 229233239, 389397401, 401409419, 409419421, 449457461, 701709719, 773787797, 787797809, 797809811, 140914231427, 157915831597, 163716571663, 202920392053, 212921312137, 252125312539, 259125932609, 263326472657, 268926932699
Offset: 1
5711 is in the sequence because the concatenation of [5, 7, 11] = 5711 which is prime. The sum [5 + 7 + 11] = 23 is another prime.
111317 is in the sequence because the concatenation of [11, 13, 17] = 111317 which is prime. The sum [11 + 13 + 17] = 41 is another prime.
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A244163:= proc() local a,b,c,k,m; a:=ithprime(n); b:=ithprime(n+1); c:=ithprime(n+2); m:=a+b+c; k:=parse(cat(a,b,c)); if isprime(k) and isprime(m) then RETURN (k); fi; end: seq(A244163 (), n=1..500);
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prQ[{a_,b_,c_}]:=Module[{p=FromDigits[Flatten[IntegerDigits/@ {a,b,c}]]}, If[ AllTrue[ {p,a+b+c},PrimeQ],p,Nothing]]; prQ/@Partition[ Prime[ Range[ 500]],3,1] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jan 05 2021 *)
A244186
Primes which are the concatenation of five consecutive primes p, q, r, s, t while the sum (p + q + r + s + t) is another prime.
Original entry on oeis.org
711131719, 5359616771, 6771737983, 149151157163167, 401409419421431, 479487491499503, 757761769773787, 14091423142714291433, 18111823183118471861, 21132129213121372141, 26892693269927072711, 27192729273127412749, 36133617362336313637, 37613767376937793793
Offset: 1
711131719 is in the sequence because the concatenation of [7, 11, 13, 17, 19] = 711131719 which is prime. The sum [7 + 11 + 13 + 17 + 19] = 67 is another prime.
5359616771 is in the sequence because the concatenation of [53, 59, 61, 67, 71] = 5359616771 which is prime. The sum [53 + 59 + 61 + 67 + 71] = 311 is another prime.
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FromDigits[Flatten[IntegerDigits/@#]]&/@Select[Partition[Prime[Range[ 1000]],5,1],AllTrue[{Total[#],FromDigits[Flatten[ IntegerDigits/@ #]]}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Dec 24 2014 *)
A385536
Integers k formed by the concatenation of 3 consecutive prime numbers such that k is divisible by at least one of those 3 primes.
Original entry on oeis.org
235, 357, 71113, 374143, 616771, 167173179, 143914471451, 909071909089909091, 104651162787110465116278991046511627907
Offset: 1
235 is a term, since it is the concatenation of the consecutive primes 2, 3, 5 and is divisible by 5.
2, 3 and 5: 235 = 5*47
3, 5, and 7: 357 = 3*119 = 7*51
7, 11 and 13: 71113 = 7*10159
37, 41 and 43: 374143 = 43*8701
61, 67 and 71: 616771 = 61*10111
167, 173 and 179: 167173179 = 167*1001037
1439, 1447 and 1451: 143914471451 = 1447*99457133
909071, 909089 and 909091: 909071909089909091 = 909091*999979000001
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tcat:= proc(a,b,c)
c + (b + 10^(1+ilog10(b))*a)*10^(1+ilog10(c))
end proc:
R:= NULL: count:= 0:
q:= 2: r:= 3:
while count < 8 do
p:= q; q:= r; r:= nextprime(r);
x:= tcat(p,q,r);
if igcd(x,p*q*r)>1 then
R:= R,x; count:= count+1;
fi
od:
R; # Robert Israel, Jul 06 2025
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cat[s_] := FromDigits[Flatten[IntegerDigits[s]]]; q[s_] := AnyTrue[s, Divisible[cat[s], #] &]; cat /@ Select[Partition[Prime[Range[72000]], 3, 1], q] (* Amiram Eldar, Jul 03 2025 *)
Showing 1-7 of 7 results.
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