A154315 Numbers k such that the number of prime digits in prime(k) equals the number of even digits in prime(k).

1, 5, 8, 10, 14, 15, 19, 23, 27, 28, 38, 39, 43, 46, 47, 50, 56, 61, 70, 77, 83, 85, 92, 97, 100, 104, 112, 113, 115, 120, 126, 127, 135, 136, 143, 144, 146, 149, 155, 156, 157, 158, 161, 163, 166, 167, 170, 173, 175, 177, 183, 184, 185, 189, 192, 195, 201, 208

Offset

1,2

Links

Table of n, a(n) for n=1..58.

Maple

noPrimDgs := proc(n) a := 0 ; for d in convert(n, base, 10) do if d in {2, 3, 5, 7} then a := a+1 ; end if; end do; a ; end proc:
noEvDgs := proc(n) a := 0 ; for d in convert(n, base, 10) do if type(d , 'even') then a := a+1 ; end if; end do; a ; end proc:
for n from 1 to 300 do p := ithprime(n) ; if noPrimDgs(p) = noEvDgs(p) then printf("%d, ", n) ; end if; end do: # R. J. Mathar, May 01 2010
# Alternative:
q:= k-> 0=add([1, 0$2, -1, 1, -1, 1, -1, 1, 0][i+1], i=convert(ithprime(k), base, 10)):
select(q, [$1..208])[];  # Alois P. Heinz, Mar 19 2026

Crossrefs

Sequence in context: A205676 A352676 A098594 * A182084 A262707 A257046

Adjacent sequences: A154312 A154313 A154314 * A154316 A154317 A154318

Keyword

nonn,base,less

Author

Juri-Stepan Gerasimov, Jan 15 2009

Extensions

Corrected(8, 23 inserted, 26 replaced by 27, 29 by 28, 97 inserted ...) by R. J. Mathar, May 01 2010

Status

approved