A241525 a(n) is the smallest start of a run of exactly n consecutive primes such that the sum of the digits of each prime is composite.

19, 17, 13, 521, 509, 503, 499, 491, 14153, 25793, 25771, 37663, 37657, 98729, 98717, 98713, 98711, 98689, 98669, 98663, 98641, 98639, 98627, 98621, 98597, 98573, 69794393, 69794383, 268684679, 268684651, 268684627, 329788829, 545497787, 545497769, 545497759, 545497753, 545497747, 545497741, 545497727, 545497723, 545497691, 545497681, 545497679, 545497637, 545497633, 545497609

Offset

1,1

Comments

No more terms below 2^32

Links

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

Example

a(3)=13 because the run of the 3 consecutive primes {13, 17, 19} is such that the sum of digits for each prime is {4, 8, 10}.

Prog

(UBASIC)
   10   P=1:KM=0:K=0:'puzzle 1290, Meller
   20   P=nxtprm(P):if P>2^32-20 then end
   30   gosub *SODP:if S<>prmdiv(S) then K=K+1:Q=P:goto 20
   40   if K>KM then print K, Q:KM=K
   50   K=0:goto 20
  200   *SODP:S=0:L=alen(P)
  210   for I=1 to L:D=val(mid(str(P), I+1, 1))
  220   S=S+D:next I
  230   return

Crossrefs

Cf. A240598.

Sequence in context: A135734 A215021 A215085 * A321332 A109410 A230339

Adjacent sequences: A241522 A241523 A241524 * A241526 A241527 A241528

Keyword

nonn,base

Author

Carlos Rivera, Apr 24 2014

Status

approved