cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A095375 Total number of 1's in the binary expansions of the first n primes: summatory A014499.

Original entry on oeis.org

1, 3, 5, 8, 11, 14, 16, 19, 23, 27, 32, 35, 38, 42, 47, 51, 56, 61, 64, 68, 71, 76, 80, 84, 87, 91, 96, 101, 106, 110, 117, 120, 123, 127, 131, 136, 141, 145, 150, 155, 160, 165, 172, 175, 179, 184, 189, 196, 201, 206, 211, 218, 223, 230, 232, 236, 240, 245, 249, 253
Offset: 1

Views

Author

Labos Elemer, Jun 07 2004

Keywords

Examples

			n=4: first 4 primes={10,11,101,111}, with a(4)=8 digits 1.
		

Crossrefs

Programs

  • Maple
    read("transforms") :
    A095375 := proc(n)
        local a;
        a := 0 ;
        for i from 1 to n do
            a := a+wt(ithprime(i)) ;
        end do:
    end proc: # R. J. Mathar, Jul 13 2012
    # second Maple program:
    a:= proc(n) option remember; `if`(n=0, 0, a(n-1)
          +add(i, i=Bits[Split](ithprime(n))))
        end:
    seq(a(n), n=1..100);  # Alois P. Heinz, Jun 26 2021
  • Mathematica
    lib[x_] :=Count[IntegerDigits[x, 2], 1] {s=0, ta=Table[0, {256}]}; Do[s=s+lib[Prime[n]]; ta[[n]]=s, {n, 1, 256}] ta
  • PARI
    a(n)=my(s);forprime(p=2,prime(n),s+=hammingweight(p));s \\ Charles R Greathouse IV, Mar 29 2013
    
  • Python
    from sympy import primerange, prime
    def A095375(n): return sum(p.bit_count() for p in primerange(prime(n)+1)) # Chai Wah Wu, Nov 12 2024