A104772 -id:A104772 - cp's OEIS frontend

A104773 A104772(A104772(n)).

1, 2, 15, 4, 65, 42, 161, 78, 185, 114, 201, 310, 305, 186, 365, 222, 381, 610, 485, 470, 545, 530, 1969, 1246, 917, 402, 681, 678, 1585, 1570, 1169, 830, 905, 890, 921, 1510, 1293, 2954, 2321, 654, 1101, 1810, 1205, 2486, 1757, 762, 4609, 2110, 1385, 834

Offset: 1

Reinhard Zumkeller, Mar 24 2005

nonn

A104774(a(n)) = A104772(n);

a(odd) = odd and a(even) = even.

A104774 a(1) = 1, a(2) = 2, a(3) = 0, a(4) = 4, and for n > 4, if n is an even number, a(n) = a(n/2) - (1 if a(n/2) is not zero), otherwise if n is an odd semiprime p*q (with q >= p), then a(n) = p+q, otherwise 0.

Original entry on oeis.org

1, 2, 0, 4, 0, 0, 0, 3, 6, 0, 0, 0, 0, 0, 8, 2, 0, 5, 0, 0, 10, 0, 0, 0, 10, 0, 0, 0, 0, 7, 0, 1, 14, 0, 12, 4, 0, 0, 16, 0, 0, 9, 0, 0, 0, 0, 0, 0, 14, 9, 20, 0, 0, 0, 16, 0, 22, 0, 0, 6, 0, 0, 0, 0, 18, 13, 0, 0, 26, 11, 0, 3, 0, 0, 0, 0, 18, 15, 0, 0, 0, 0, 0, 8, 22, 0, 32, 0, 0, 0, 20, 0, 34, 0, 24

Offset: 1

Reinhard Zumkeller, Mar 24 2005

nonn

The original name was: If n is even then (if n<=4 then n else a(n/2) + 0^a(n/2) - 1) else (if n=p*q is semiprime then p+q else 0^(n-1))).

Antti Karttunen, Table of n, a(n) for n = 1..16384
Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

Cf. A001358, A046315, A090967, A104772, A104773.

A104774(n) = if(!(n%2),if(n<=4,n,my(u=A104774(n/2)); (u+!u-1)),if(2==bigomega(n),my(f=factor(n)[,1]); if(1==omega(n),2*f[1],f[1]+f[2]), !(n-1))); \\ Antti Karttunen, Mar 30 2021

a(A104772(n)) = n; a(A104773(n)) = A104772(n).

Name changed by Antti Karttunen, Apr 01 2021

cp's OEIS Frontend

A104773 A104772(A104772(n)).

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A104774 a(1) = 1, a(2) = 2, a(3) = 0, a(4) = 4, and for n > 4, if n is an even number, a(n) = a(n/2) - (1 if a(n/2) is not zero), otherwise if n is an odd semiprime p*q (with q >= p), then a(n) = p+q, otherwise 0.

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