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A342801 Primes p such that, if b is the sum of digits of p, y = p mod b and x = (p-y)/b, then p-x*y, p+x*y, x+y and x-y are all prime. 1
127, 173, 181, 257, 281, 359, 563, 569, 577, 719, 751, 1061, 1381, 1879, 1901, 4327, 4759, 5441, 6397, 6977, 7207, 7933, 8387, 8419, 8521, 9349, 10009, 10891, 11311, 11443, 11467, 12323, 13567, 13873, 14369, 14929, 15299, 15683, 16073, 17351, 18041, 18749, 24407, 24481, 24767, 25819, 27067, 27739 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

EXAMPLE

a(3) = 181 is a term because 181 is prime, with sum of digits b=10, y=1, x=18, and n-x*y=163, n+x*y=199, x+y=19, and x-y=17 are all prime.

MAPLE

filter:= proc(n) local b, x, y;

    if not isprime(n) then return false fi;

    b:= convert(convert(n, base, 10), `+`);

    if b <= 1 then return false fi;

    y:= n mod b;

    x:= (n-y)/b;

    isprime(n-x*y) and isprime(n+x*y) and isprime(x+y) and isprime(x-y)

end proc:

select(filter, [2, seq(i, i=3..10^5, 2)]);

CROSSREFS

Sequence in context: A094933 A156702 A180536 * A137985 A065092 A141916

Adjacent sequences:  A342798 A342799 A342800 * A342802 A342803 A342804

KEYWORD

nonn,base

AUTHOR

J. M. Bergot and Robert Israel, Mar 21 2021

STATUS

approved

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Last modified June 13 05:37 EDT 2021. Contains 344981 sequences. (Running on oeis4.)