A070942 Values of n such that the first n terms of A055265 constitute a permutation of {1,2,3,...,n}.

1, 2, 3, 4, 7, 8, 9, 10, 17, 18, 19, 22, 23, 24, 43, 55, 56, 57, 73, 99, 136, 137, 142, 143, 202, 217, 218, 233, 234, 264, 281, 282, 287, 288, 289, 302, 303, 304, 387, 409, 414, 415, 491, 509, 520, 521, 528, 529, 532, 533, 553, 554, 555, 588, 652, 653, 654, 665

Offset

1,2

Links

Zak Seidov and Robert Israel, Table of n, a(n) for n = 1..1500 (first 286 terms from Zak Seidov)

Maple

S:= {1}: L:= {}:
a[1]:= 1: b[1]:= 1:
count:= 1:
for n from 2 to 10000 do
  for k in L do
    if isprime(k+b[n-1]) then
      b[n]:= k;
      S:= S union {k};
      L:= L minus {k};
      if L = {} then
        count:= count+1;
        a[count]:= n;
      fi;
      break;
    fi
  od:
  if not assigned(b[n]) then
    for k from max(S) + 1 do
      if isprime(k+b[n-1]) then
        b[n]:= k;
        if k = max(S) + 1 and L = {} then
           count:= count+1;
           a[count]:= n;
        fi;
        S:= S union {k};
        L:= {$1..k} minus S;
        break
      fi
    od
  fi;
od:
seq(a[i], i=1..count); # Robert Israel, Sep 10 2014

Crossrefs

Cf. A055265.

Sequence in context: A261412 A112965 A152979 * A073798 A124375 A287664

Adjacent sequences: A070939 A070940 A070941 * A070943 A070944 A070945

Keyword

nonn

Author

John W. Layman, Apr 15 2003

Status

approved