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.

A190376 a(n) = sum (in ordinary arithmetic) of A067399(k), for k from 2^n to 2^(n+1)-1.

Original entry on oeis.org

1, 4, 12, 31, 75, 175, 393, 864, 1868, 3978, 8394
Offset: 0

Views

Author

N. J. A. Sloane, May 09 2011

Keywords

Comments

I was hoping this would turn out to be a known sequence, in which case we would learn something about the average values of A067399.

Crossrefs

Programs

  • Maple
    read("transforms");
    numbralADD := proc(a,b) option remember; ORnos(a,b) ; end proc:
    numbralMUL := proc(a,b) option remember; local p,bshf,s ; p := 0 ; bshf := b ; for s from 0 do if bshf mod 2 <> 0 then p := numbralADD(p, 2^s*a ) ; end if; bshf := floor(bshf/2) ; if bshf = 0 then return p; end if; end do; end proc:
    isnumbralDiv := proc(n,d) option remember; for e from 0 do if numbralMUL(e,d) = n then return true; elif numbralMUL(e,d) > 2*n then return false; end if; end do: end proc:
    numbralDivisors := proc(n) option remember; local d,i; d := {} ; for i from 1 to n do if isnumbralDiv(n,i) then d := d union {i} ; end if; end do: d ; end proc:
    A067399 := proc(n) nops(numbralDivisors(n)) ; end proc:
    A190376 := proc(n) add(A067399(k),k=2^n..2^(n+1)-1) ; end proc: # R. J. Mathar, May 30 2011