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A065967
a(n) = n * Sum_{primes p dividing n} (1 + 1/p).
1
0, 3, 4, 6, 6, 17, 8, 12, 12, 27, 12, 34, 14, 37, 38, 24, 18, 51, 20, 54, 52, 57, 24, 68, 30, 67, 36, 74, 30, 121, 32, 48, 80, 87, 82, 102, 38, 97, 94, 108, 42, 167, 44, 114, 114, 117, 48, 136, 56, 135, 122, 134, 54, 153, 126, 148, 136, 147, 60, 242
OFFSET
1,2
LINKS
MAPLE
A065967 := proc(n) local i, j, k, t1, t2, t3; t1 := ifactors(n)[2]; t2 := n^1*add((1+1/(t1[i][1])^1), i=1..nops(t1)); end;
PROG
(PARI) { for (n=1, 1000, s=0; p=2; while (p<=n, if(n%p == 0, s+=(1 + 1/p)); p=nextprime(p + 1)); write("b065967.txt", n, " ", n*s) ) } \\ Harry J. Smith, Nov 05 2009
CROSSREFS
Sequence in context: A285895 A220345 A349217 * A345209 A117986 A248738
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Dec 09 2001
STATUS
approved