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A088685
Records for the sum-of-primes function sopfr(n) if sopfr(prime) is taken to be 0.
5
0, 4, 5, 6, 7, 9, 10, 13, 15, 19, 21, 25, 31, 33, 39, 43, 45, 49, 55, 61, 63, 69, 73, 75, 81, 85, 91, 99, 103, 105, 109, 111, 115, 129, 133, 139, 141, 151, 153, 159, 165, 169, 175, 181, 183, 193, 195, 199, 201, 213, 225, 229, 231, 235, 241, 243, 253, 259, 265, 271
OFFSET
1,2
COMMENTS
A048974, A052147 and A067187 are very similar after dropping terms less than 13. - Eric W. Weisstein, Oct 10 2003
LINKS
Eric Weisstein's World of Mathematics, Sum of Prime Factors
MATHEMATICA
Union@ FoldList[Max, Table[Total@ Flatten@ Map[ConstantArray[#1, #2] /. 1 -> 0 & @@ # &, FactorInteger@ n] - n Boole[PrimeQ@ n], {n, 540}]] (* Michael De Vlieger, Jun 29 2017 *)
PROG
(PARI) sopfr(k) = my(f=factor(k)); sum(j=1, #f~, f[j, 1]*f[j, 2]);
lista(nn) = {my(record = -1); for (n=1, nn, if (! isprime(n), if ((x=sopfr(n)) > record, record = x; print1(record, ", ")); ); ); } \\ Michel Marcus, Jun 29 2017
(Python)
from sympy import factorint, isprime
def sopfr(n):
f=factorint(n)
return sum([i*f[i] for i in f])
l=[]
record=-1
for n in range(1, 501):
if not isprime(n):
x=sopfr(n)
if x>record:
record=x
l.append(record)
print(l) # Indranil Ghosh, Jun 29 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Eric W. Weisstein, Oct 05 2003
STATUS
approved