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A175429 Number of primes that are permutations of first n primes. 2
1, 1, 1, 8, 20, 112, 608, 4436, 34843, 0, 4785242 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..11.

Zak Seidov, Primes from first 6 primes

Zak Seidov, Primes from first 7 primes

Zak Seidov, Primes from first 8 primes

EXAMPLE

a(1)=1: 2; a(2)=1: 23; a(3)=1, 523;

a(4)=8: {2357,2753,3257,3527,5237,5273,7253,7523};

a(5)=20: {112573, 115237,...,735211, 751123}, see A177275;

a(6)=112: {11132357,11132753,...,75231113,75311213}, see links;

a(7)=608: {1113257317,1113321757,...,7523131711,7523171311}, see links;

a(8)= 4436: {111317193257,111317193527,...,753191321117,753217131911}, see links;

a(9)= 34843: {11131719223357,11131719235237,...,75323217191113,75323219131117}

a(10)=0 because sum of digits of first 10 primes (2+3+5+7+(1+1)+(1+3)+(1+7)+(1+9)+(2+3)+(2+9))=57 is multiple of 3.

MAPLE

with(numtheory): with(combinat): P:=proc(q) local a, b, c, j, k, n, t;

a:=[]; for n from 1 to q do a:=[op(a), ithprime(n)]; b:=permute(a);

t:=0; for k from 1 to nops(b) do c:=0; for j from 1 to nops(b[k]) do

c:=10^(ilog10(b[k][j])+1)*c+b[k][j]; od; if isprime(c) then t:=t+1; fi; od; print(t); od; end: P(11); # Paolo P. Lava, Nov 17 2017

CROSSREFS

Cf. A177275.

Sequence in context: A215181 A014584 A074472 * A094253 A208084 A214905

Adjacent sequences:  A175426 A175427 A175428 * A175430 A175431 A175432

KEYWORD

base,nonn

AUTHOR

Zak Seidov, May 10 2010

STATUS

approved

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Last modified December 11 04:22 EST 2017. Contains 295860 sequences.