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A305976
Filter sequence for a(prime^k) = constant sequences.
7
1, 2, 2, 2, 2, 3, 2, 2, 2, 4, 2, 5, 2, 6, 7, 2, 2, 8, 2, 9, 10, 11, 2, 12, 2, 13, 2, 14, 2, 15, 2, 2, 16, 17, 18, 19, 2, 20, 21, 22, 2, 23, 2, 24, 25, 26, 2, 27, 2, 28, 29, 30, 2, 31, 32, 33, 34, 35, 2, 36, 2, 37, 38, 2, 39, 40, 2, 41, 42, 43, 2, 44, 2, 45, 46, 47, 48, 49, 2, 50, 2, 51, 2, 52, 53, 54, 55, 56, 2, 57, 58, 59, 60, 61, 62, 63, 2, 64, 65, 66, 2
OFFSET
1,2
LINKS
FORMULA
a(1) = 1, for n > 1, if A010055(n) = 1 [when n is in A246655], a(n) = 2, otherwise a(n) = 2+A085970(n) = running count from 3 onward.
PROG
(PARI)
up_to = 100000;
partialsums(f, up_to) = { my(v = vector(up_to), s=0); for(i=1, up_to, s += f(i); v[i] = s); (v); }
v065515 = partialsums(n -> (omega(n)<=1), up_to);
A065515(n) = v065515[n];
A085970(n) = (n - A065515(n));
A305976(n) = if(1==n, n, if(isprimepower(n), 2, 2+A085970(n)));
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 02 2018
STATUS
approved