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A191583 Sum of the distinct prime divisors of prime(n) + prime(n+1). 3
5, 2, 5, 5, 5, 10, 5, 12, 15, 10, 19, 18, 12, 10, 7, 9, 10, 2, 28, 5, 21, 5, 45, 36, 16, 22, 17, 5, 42, 10, 48, 69, 28, 5, 10, 20, 7, 21, 24, 13, 10, 36, 5, 23, 16, 48, 40, 10, 24, 23, 61, 10, 46, 129, 20, 28, 10, 139, 36, 52, 5, 10, 108, 18, 17, 5, 169, 24 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
a(n) = A008472(A001043(n)). [Reinhard Zumkeller, Jun 28 2011]
LINKS
EXAMPLE
a(6) = 10 because prime(6) + prime(7) = 13+17 = 30 = 2*3*5 and 2+3+5 = 10.
MAPLE
with(numtheory):for n from 1 to 100 do:x:=ithprime(n)+ithprime(n+1):y:=factorset(x):n1:=nops(y):s:=0:for k from 1 to n1 do:s:=s+y[k]:od:printf(`%d, `, s):od:
MATHEMATICA
sdpd[n_]:=Total[Transpose[FactorInteger[n]][[1]]]; sdpd/@(Total/@ Partition[ Prime[Range[70]], 2, 1]) (* Harvey P. Dale, Mar 18 2012 *)
PROG
(PARI) vecsum(v)=sum(i=1, #v, v[i])
p=2; forprime(q=3, 1e3, print1(vecsum(factor(p+q)[, 1])", "); p=q)
\\ Charles R Greathouse IV, Jun 12 2011
CROSSREFS
Sequence in context: A199957 A020855 A007292 * A116558 A196626 A082571
KEYWORD
nonn
AUTHOR
Michel Lagneau, Jun 07 2011
STATUS
approved

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Last modified July 24 20:07 EDT 2024. Contains 374585 sequences. (Running on oeis4.)