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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. 3
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS 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))). LINKS Antti Karttunen, Table of n, a(n) for n = 1..16384 Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537 FORMULA a(A104772(n)) = n; a(A104773(n)) = A104772(n). PROG (PARI) 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 CROSSREFS Cf. A001358, A046315, A090967, A104772, A104773. Sequence in context: A218862 A243199 A305212 * A087263 A099894 A048298 Adjacent sequences: A104771 A104772 A104773 * A104775 A104776 A104777 KEYWORD nonn AUTHOR Reinhard Zumkeller, Mar 24 2005 EXTENSIONS Name changed by Antti Karttunen, Apr 01 2021 STATUS approved

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Last modified March 30 16:58 EDT 2023. Contains 361622 sequences. (Running on oeis4.)