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A157478 Symmetrical Prime numbers : Prime-+n are primes, 1,2,3,4...x times. 0
5, 11, 17, 37, 53, 89, 107, 127, 179, 197, 223, 233, 257, 263, 401, 409, 421, 449, 457, 661 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

5-+2(primes); 11-+6,11-+8(primes); 17-+6,17-+12,17-+14(primes); 37-+6,37-+24,37-+30,37-+34(primes); 53-+6,30,36,48,50; 89-+18,42,48,60,78,84,... prime number 5 symmetrical 1 time, prime number 11 symmetrical 2 times, prime number 17 symmetrical 3 times, ...

LINKS

Table of n, a(n) for n=1..20.

MATHEMATICA

q=1; lst={}; Do[p=Prime[n]; i=0; Do[If[PrimeQ[p-k]&&PrimeQ[p+k], i++; ], {k, 2, p, 2}]; If[i==q, AppendTo[lst, p]; q++ ], {n, 2*5!}]; lst

CROSSREFS

Sequence in context: A030468 A277290 A085634 * A088903 A094205 A136091

Adjacent sequences:  A157475 A157476 A157477 * A157479 A157480 A157481

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Mar 01 2009

STATUS

approved

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Last modified November 18 10:18 EST 2017. Contains 294887 sequences.