The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A352892 Next even term in the trajectory of map x -> A341515(x), when starting from x=n; a(1) = 1. Here A341515 is the Collatz or 3x+1 map (A006370) conjugated by unary-binary-encoding (A156552). 11
 1, 2, 2, 6, 2, 2, 2, 12, 4, 8, 2, 14, 2, 18, 6, 24, 2, 6, 2, 54, 10, 50, 2, 28, 4, 98, 8, 150, 2, 2, 2, 48, 14, 242, 6, 70, 2, 338, 22, 108, 2, 8, 2, 294, 12, 578, 2, 56, 4, 20, 26, 726, 2, 12, 10, 300, 34, 722, 2, 26, 2, 1058, 20, 96, 14, 18, 2, 1014, 38, 32, 2, 140, 2, 1682, 18, 1734, 6, 50, 2, 216, 16, 1922, 2, 686 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Antti Karttunen, Table of n, a(n) for n = 1..10000 Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537 Index entries for sequences related to 3x+1 (or Collatz) problem Index entries for sequences computed from indices in prime factorization FORMULA a(n) = A348717(A341515(n)). For all n >= 1, a(2n) = A353268(2n), a(2n-1) = A348717(2n-1). a(p) = 2 for all primes p. For n > 1, a(n) = A005940(1+A139391(A156552(n))). PROG (PARI) A005940(n) = { my(p=2, t=1); n--; until(!n\=2, if((n%2), (t*=p), p=nextprime(p+1))); (t); }; A064989(n) = {my(f); f = factor(n); if((n>1 && f[1, 1]==2), f[1, 2] = 0); for (i=1, #f~, f[i, 1] = precprime(f[i, 1]-1)); factorback(f)}; A156552(n) = { my(f = factor(n), p, p2 = 1, res = 0); for(i = 1, #f~, p = 1 << (primepi(f[i, 1]) - 1); res += (p * p2 * (2^(f[i, 2]) - 1)); p2 <<= f[i, 2]); res }; A329603(n) = A005940(2+(3*A156552(n))); A341515(n) = if(n%2, A064989(n), A329603(n)); A348717(n) = { my(f=factor(n)); if(#f~>0, my(pi1=primepi(f[1, 1])); for(k=1, #f~, f[k, 1] = prime(primepi(f[k, 1])-pi1+1))); factorback(f); }; \\ From A348717 A352892(n) = A348717(A341515(n)); (PARI) A352892(n) = if(1==n, n, n = A341515(n); while(n%2, n = A341515(n)); (n)); \\ A slower alternative. CROSSREFS Cf. A000040, A005940, A064989, A156552, A329603, A341515, A348717. Cf. also A139391, A352893, A352894, A352896, A352897, A352898, A352899, A353267. Coincides with A353268 on even n, and with A348717 on odd n. Sequence in context: A077198 A046110 A296091 * A126889 A205030 A278250 Adjacent sequences: A352889 A352890 A352891 * A352893 A352894 A352895 KEYWORD nonn AUTHOR Antti Karttunen, Apr 08 2022 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified March 4 22:06 EST 2024. Contains 370532 sequences. (Running on oeis4.)