A112012 Numbers n such that there exists at least one number j and pi(m) = d_1 d_2 ... d_j*d_(j+1) d_(j+2) ... d_k where d_1 d_2 ...d_k is the decimal expansion of n.

16, 17, 73, 132, 224, 322, 342, 352, 362, 619, 1017, 1117, 1196, 1516, 2163, 2215, 3514, 3714, 5137, 11373, 12012, 12121, 13120, 17116, 21113, 25911, 51045, 64541, 64581, 64591, 64601, 64611, 64651, 64661, 64691, 64701, 64711, 64721, 100967

Offset

1,1

Comments

A112013 is the prime subsequence of this sequence.

Links

Table of n, a(n) for n=1..39.

Example

pi(16)=1*6 so j=1; pi(342)=34*2 so j=2; pi(12012)=120*12 so j=3;
pi(64541)=6454*1 so j=4, etc.

Mathematica

Select[Range[10, 200000], MemberQ[h=IntegerDigits[ # ]; k=Length[h]; Table[FromDigits[Table[h[[i]], {i, j}]]*FromDigits[Table[h[[i]], {i, j+1, k}]], {j, k}], PrimePi[ # ]] &]

Crossrefs

Cf. A112013.

Sequence in context: A097220 A041530 A041528 * A003999 A217844 A041532

Adjacent sequences: A112009 A112010 A112011 * A112013 A112014 A112015

Keyword

base,nonn

Author

Farideh Firoozbakht, Sep 04 2005

Status

approved