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A095402
Sum of digits of all distinct prime factors of n.
13
0, 2, 3, 2, 5, 5, 7, 2, 3, 7, 2, 5, 4, 9, 8, 2, 8, 5, 10, 7, 10, 4, 5, 5, 5, 6, 3, 9, 11, 10, 4, 2, 5, 10, 12, 5, 10, 12, 7, 7, 5, 12, 7, 4, 8, 7, 11, 5, 7, 7, 11, 6, 8, 5, 7, 9, 13, 13, 14, 10, 7, 6, 10, 2, 9, 7, 13, 10, 8, 14, 8, 5, 10, 12, 8, 12, 9, 9, 16, 7, 3, 7, 11, 12, 13, 9, 14, 4, 17, 10
OFFSET
1,2
LINKS
EXAMPLE
n = 1000: prime set = {2, 5}, a[1000] = 7;
n = 255255: prime set={3, 5, 7, 11, 13, 17}, a[255255]= 3+5+7+2+4+8 = 29.
MATHEMATICA
ffi[x_] :=Flatten[FactorInteger[x]] lf[x_] :=Length[FactorInteger[x]] ba[x_] :=Table[Part[ffi[x], 2*j-1], {j, 1, lf[x]}] sd[x_] :=Apply[Plus, IntegerDigits[x]] tdp[x_] :=Flatten[Table[IntegerDigits[Part[ba[x], j]], {j, 1, lf[x]}], 1] sdp[x_] :=Apply[Plus, tdp[x]] Table[sdp[w], {w, 1, 150}]
Table[Total[Flatten[IntegerDigits[First/@FactorInteger[n]]]], {n, 1, 100}] (Zak Seidov)
PROG
(Python)
from sympy import factorint
def a(n): return sum(sum(map(int, str(p))) for p in factorint(n))
print([a(n) for n in range(1, 91)]) # Michael S. Branicky, Dec 12 2023
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Labos Elemer, Jun 21 2004
STATUS
approved