A168161 Primes p which are equal to the sum of the binary digits in all primes <= p.

3, 5, 11, 19, 23, 47, 61

Offset

1,1

Comments

A subsequence of A168162.

Links

Table of n, a(n) for n=1..7.

Formula

A168161 = { prime p | p=A095375(pi(p)) }, where pi(n) = A000720(n).

Mathematica

sbdQ[n_]:=Total[Flatten[IntegerDigits[#, 2]&/@Prime[Range[PrimePi[ n]]]]] == n; Select[Prime[Range[20]], sbdQ] (* Harvey P. Dale, Feb 04 2015 *)

Prog

(PARI) s=0; forprime(p=1, 9999, if(p==s+=norml2(binary(p)), print1(p, ", ")))

Crossrefs

Cf. A217792

Sequence in context: A089439 A122516 A243899 * A217792 A284036 A172438

Adjacent sequences: A168158 A168159 A168160 * A168162 A168163 A168164

Keyword

fini,full,nonn,base

Author

M. F. Hasler, Nov 22 2009

Extensions

Cross reference added by Harvey P. Dale, Mar 26 2013

Status

approved