This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A081401 Pseudologarithm (A056239) of n!: a(n) = A056239(A000142(n)). 4
 0, 1, 3, 5, 8, 11, 15, 18, 22, 26, 31, 35, 41, 46, 51, 55, 62, 67, 75, 80, 86, 92, 101, 106, 112, 119, 125, 131, 141, 147, 158, 163, 170, 178, 185, 191, 203, 212, 220, 226, 239, 246, 260, 267, 274, 284, 299, 305, 313, 320, 329, 337, 353, 360, 368, 375, 385, 396, 413 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Alois P. Heinz, Table of n, a(n) for n = 1..1000 FORMULA a(n) = Sum(k*e(k)) where k runs through indices of prime factors of n!, while e(k) is the exponent of the corresponding prime factor. EXAMPLE n=8: 8! = 40320 = 2*2*2*2*2*2*2*3*3*5*7, p-indices = {1,2,3,4}, exponents = {7,2,1,1}; a(8) = 1*7 + 2*2 + 3*1 + 4*1 = 7 + 4 + 3 + 4 = 18. MAPLE a:= n-> add (numtheory[pi](i[1])*i[2], i=ifactors(n!)[2]): seq (a(n), n=1..100);  # Alois P. Heinz, Aug 09 2012 CROSSREFS Cf. A000142, A056239. Sequence in context: A022433 A284442 A207038 * A003311 A108279 A002821 Adjacent sequences:  A081398 A081399 A081400 * A081402 A081403 A081404 KEYWORD nonn AUTHOR Labos Elemer, Mar 31 2003 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 16 13:51 EDT 2019. Contains 328093 sequences. (Running on oeis4.)