A294952 Triangle read by rows: T(n,k) is the number of n-digit numbers having a k-digit greatest prime factor.

9, 36, 54, 95, 470, 335, 197, 2854, 3547, 2402, 356, 13370, 31999, 25577, 18698, 579, 54250, 236147, 256465, 199403, 153156, 882, 196729, 1486448, 2386859, 1999848, 1633601, 1295633, 1272, 653419, 8615121, 19298617, 19999102, 16384481, 13828384, 11219604

Offset

1,1

Comments

By convention, gpf(1) = 1; see A006530.

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..66

Example

Table begins
     9;
    36,     54;
    95,    470,     335;
   197,   2854,    3547,     2402;
   356,  13370,   31999,    25577,    18698;
   579,  54250,  236147,   256465,   199403,  153156;
   882, 196729, 1486448,  2386859,  1999848,  1633601,  1295633;
  1272, 653419, 8615121, 19298617, 19999102, 16384481, 13828384, 11219604;

Prog

(PARI) row(n)=if(n<2, return([9])); my(v=vector(n)); forfactored(k=10^(n-1), 10^n-1, v[#Str(vecmax(k[2][, 1]))]++); v \\ Charles R Greathouse IV, Nov 12 2017

Crossrefs

Cf. A006530.

First column gives A085630.

Sequence in context: A329808 A169580 A258844 * A068810 A077115 A297584

Adjacent sequences: A294949 A294950 A294951 * A294953 A294954 A294955

Keyword

nonn,base,tabl

Author

Jon E. Schoenfield, Nov 11 2017

Status

approved