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A084194 Even numbers n such that the sum of the digits is prime and the sum of the digits of n/2 is also prime. 3
14, 32, 50, 58, 76, 94, 98, 104, 122, 140, 148, 166, 184, 188, 212, 230, 238, 256, 274, 278, 292, 296, 302, 320, 328, 346, 364, 368, 382, 386, 410, 418, 436, 454, 458, 472, 476, 490, 494, 500, 508, 526, 544, 548, 562, 566, 580, 584 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Sometimes n/2 is prime.

LINKS

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

EXAMPLE

3+2=5 for n=32 and 1+6=7 for n/2=16;

5+8=13 for n=58 and 2+9=11 for n/2=29;

2+1+2=5 for n=212 and 1+0+6=7 for n/2=106;

2+5+6=13 for n=256 and 1+2+8=11 for n/2=128.

MAPLE

filter:= proc(n)

  isprime(convert(convert(n, base, 10), `+`)) and isprime(convert(convert(n/2, base, 10), `+`))

end proc:

select(filter, [seq(i, i=2..1000, 2)]); # Robert Israel, Sep 04 2019

PROG

(PARI) isok(n) = {if (n % 2, return (0)); dn = digits(n); dh = digits(n/2); isprime(sum(i=1, #dn, dn[i])) && isprime(sum(i=1, #dh, dh[i])); } \\ Michel Marcus, Aug 12 2013

CROSSREFS

Cf. A084201.

Sequence in context: A101183 A101444 A222414 * A031109 A155819 A120711

Adjacent sequences:  A084191 A084192 A084193 * A084195 A084196 A084197

KEYWORD

base,nonn

AUTHOR

Patrick Capelle, Jun 20 2003

EXTENSIONS

More terms from Michel Marcus, Aug 12 2013

STATUS

approved

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Last modified October 18 05:39 EDT 2019. Contains 328146 sequences. (Running on oeis4.)