A084195 Even numbers n such that the sum of the digits is prime, n/2 is prime and the sum of the digits of n/2 is also prime.

14, 58, 94, 122, 166, 274, 278, 302, 346, 382, 386, 454, 458, 526, 562, 566, 634, 674, 706, 746, 818, 922, 926, 1114, 1154, 1198, 1202, 1282, 1286, 1466, 1514, 1594, 1642, 1646, 1774, 1822, 1954, 2038, 2078, 2102, 2182, 2186, 2218, 2258, 2326, 2362

Offset

1,1

Links

Table of n, a(n) for n=1..46.

Example

5+8=13 for n=58 and 2+9=11 for n/2=29=prime.
1+2+2=5 for n=122 and 6+1=7 for n/2=61=prime.
2+7+8=17 for n=278 and 1+3+9=13 for n/2=139=prime.

Prog

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

Crossrefs

Subsequence of A084194.

Sequence in context: A212675 A041376 A063537 * A033856 A143861 A100174

Adjacent sequences: A084192 A084193 A084194 * A084196 A084197 A084198

Keyword

base,nonn

Author

Patrick Capelle, Jun 20 2003

Extensions

More terms from Michel Marcus, Aug 12 2013

Status

approved