A241895 Primes p equal to the sum in base 3 of the digits of all primes <= p.

3, 37, 695663, 695881, 1308731, 1308757, 1313153, 1314301, 1326097, 1766227, 3204779, 14328191

Offset

1,1

Links

Table of n, a(n) for n=1..12.

Formula

prime(n) such that, using base 3, prime(n) = sum_{1..n} A239619(i).

Example

3 = digit-sum(primes <= 3,base=3) = sum(2) + sum(1,0). 37 = digit-sum(primes <= 37,base=3) = sum(2) + sum(1,0) + sum(1,2) + sum(2,1) + sum(1,0,2) + sum(1,1,1) + sum(1,2,2) + sum(2,0,1) + sum(2,1,2) + sum(1,0,0,2) + sum(1,0,1,1) + sum(1,1,0,1).

Prog

(PARI) sdt(n) = my(d = digits(n, 3)); sum(i=1, #d, d[i]);
lista(nn) = {sp = 0; forprime(p=1, nn, sp += sdt(p); if (p == sp, print1(p, ", ")); ); } \\ Michel Marcus, May 02 2014

Crossrefs

Cf. A168161 (similar in base 2), A240886 (similar but excluding p from the sum).

Sequence in context: A284411 A176245 A122787 * A093939 A129122 A345688

Adjacent sequences: A241892 A241893 A241894 * A241896 A241897 A241898

Keyword

nonn,more,base

Author

Anthony Sand, May 01 2014

Status

approved