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A350661
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a(1) = 1; a(n) = a(A007947(n) - 1) + n.
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0
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1, 3, 6, 5, 10, 16, 23, 9, 12, 22, 33, 22, 35, 49, 64, 17, 34, 28, 47, 32, 53, 75, 98, 34, 30, 56, 30, 63, 92, 122, 153, 33, 66, 100, 135, 46, 83, 121, 160, 52, 93, 135, 178, 97, 94, 140, 187, 58, 65, 62, 113, 82, 135, 64, 119, 91, 148, 206, 265, 152, 213, 275, 95, 65
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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FORMULA
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a(1) = 1; a(n) = a(A075423(n)) + n.
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EXAMPLE
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a(3) = a(2) + 3 = a(1) + 5 = 6;
a(6) = a(5) + 6 = a(4) + 11 = a(1) + 15 = 16.
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MATHEMATICA
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rad[n_] := Times @@ First /@ FactorInteger[n]; a[1] = 1; a[n_] := a[n] = a[rad[n] - 1] + n; Array[a, 100] (* Amiram Eldar, Jan 10 2022 *)
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PROG
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(Python)
from sympy import prod, primefactors
from functools import lru_cache
rad = lambda n: prod(primefactors(n))
@lru_cache()
def a(n):
if n == 1: return 1
return a(rad(n)-1)+n
print([a(i) for i in range(1, 100)])
(PARI) rad(n) = factorback(factorint(n)[, 1]); \\ A007947
a(n) = if (n==1, 1, a(rad(n) - 1) + n); \\ Michel Marcus, Jan 10 2022
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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