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A173733 Primes p which give primes when 1331 = 11^3 is prefixed (see A173579). 3
3, 17, 53, 83, 107, 227, 251, 269, 293, 347, 383, 431, 443, 521, 587, 599, 641, 647, 683, 719, 761, 773, 821, 857, 929, 1031, 1097, 1217, 1223, 1301, 1367, 1409, 1433, 1451, 1619, 1637, 1709, 1787, 1973, 2081, 2087, 2129, 2399, 2477, 2591, 2633, 2657, 2693 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

N = 1331 = 11^3, p k-digit prime, to check if q = N * 10^k + p is prime

With exception of 3 necessarily p of form 3k+2, as sod(1331 = 8)

REFERENCES

K. Haase, P. Mauksch: Spass mit Mathe, Urania-Verlag Leipzig, Verlag Dausien Hanau, 2. Auflage 1985

Helmut Kracke, Mathe-musische Knobelisken, Duemmler Bonn, 2. Auflage 1983

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

13313 = prime(1581) => a(1) = prime(2) = 3

133117 = prime(12425) => a(2) = prime(7) = 17

133153 = prime(12427) => a(3) = prime(16) = 53

13311217 = prime(868166) => a(28) = prime(199) = 1217

13311223 = prime(868167) => a(29) = prime(200) = 1223

Note: two consecutive primes P = prime(n), Q = prime(n+1) yield consecutive prime concatenations "N P" = prime(m) and "N Q" = prime(m+1)

MATHEMATICA

Select[Prime[Range[400]], PrimeQ[FromDigits[Join[{1, 3, 3, 1}, IntegerDigits[ #]]]]&] (* Harvey P. Dale, Jun 09 2015 *)

CROSSREFS

Cf. A102006, A167535, A168147, A168219, A168274, A173579

Sequence in context: A225727 A163943 A093418 * A258032 A033562 A212415

Adjacent sequences:  A173730 A173731 A173732 * A173734 A173735 A173736

KEYWORD

nonn,base,less

AUTHOR

Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Feb 23 2010

EXTENSIONS

Edited and extended by Charles R Greathouse IV, Apr 24 2010

STATUS

approved

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Last modified September 21 15:13 EDT 2017. Contains 292300 sequences.