login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A107737 Numbers n such that, in prime decomposition of n, sum of all prime factors and their orders is prime. 3
2, 6, 8, 9, 14, 25, 26, 30, 32, 38, 40, 45, 56, 63, 66, 70, 74, 75, 81, 86, 88, 96, 99, 100, 104, 117, 121, 130, 134, 136, 138, 144, 147, 153, 154, 158, 160, 168, 174, 184, 190, 194, 196, 206, 207, 216, 218, 238, 248, 250, 252, 254, 266, 275, 279, 280, 286, 289 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Corresponding primes in A107738. Cf. A008474 If n = Product (p_j^k_j) then a(n) = Sum (p_j + k_j).

LINKS

Table of n, a(n) for n=1..58.

Eric Weisstein's World of Mathematics, Prime Factorization

EXAMPLE

n = 104 OK because 104 = 2^3 * 13^1 => (2+3)+(13+1) = 19 is prime.

MATHEMATICA

ta=Table[Plus @@ Flatten[FactorInteger[n]], {n, 300}]; bb={}; Do[If[PrimeQ[t=ta[[i]]], bb=Append[bb, {i, t}]], {i, 300}]; tr=Transpose[bb]; A107738=tr[[2]]; A107737=tr[[1]]

CROSSREFS

Cf. A008474, A107738.

Sequence in context: A047278 A242204 A172209 * A045138 A067704 A192125

Adjacent sequences:  A107734 A107735 A107736 * A107738 A107739 A107740

KEYWORD

nonn

AUTHOR

Zak Seidov, May 23 2005

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 7 17:16 EST 2016. Contains 278890 sequences.