login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A286535
Restricted growth sequence of A278535 (prime-signature of A253565).
3
1, 2, 2, 3, 2, 3, 4, 5, 2, 3, 4, 5, 4, 6, 6, 7, 2, 3, 4, 5, 4, 6, 6, 7, 4, 6, 8, 9, 6, 10, 9, 11, 2, 3, 4, 5, 4, 6, 6, 7, 4, 6, 8, 9, 6, 10, 9, 11, 4, 6, 8, 9, 8, 12, 12, 13, 6, 10, 12, 14, 9, 14, 13, 15, 2, 3, 4, 5, 4, 6, 6, 7, 4, 6, 8, 9, 6, 10, 9, 11, 4, 6, 8, 9, 8, 12, 12, 13, 6, 10, 12, 14, 9, 14, 13, 15, 4, 6, 8, 9, 8, 12, 12, 13, 8, 12, 16, 17, 12, 18
OFFSET
0,2
LINKS
PROG
(PARI)
rgs_transform(invec) = { my(occurrences = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(occurrences, invec[i]), my(pp = mapget(occurrences, invec[i])); outvec[i] = outvec[pp] , mapput(occurrences, invec[i], i); outvec[i] = u; u++ )); outvec; };
write_to_bfile(start_offset, vec, bfilename) = { for(n=1, length(vec), write(bfilename, (n+start_offset)-1, " ", vec[n])); }
A046523(n) = { my(f=vecsort(factor(n)[, 2], , 4), p); prod(i=1, #f, (p=nextprime(p+1))^f[i]); }; \\ This function from Charles R Greathouse IV, Aug 17 2011
A061395(n) = if(1==n, 0, primepi(vecmax(factor(n)[, 1]))); \\ After M. F. Hasler's code for A006530.
A253550(n) = if(1==n, 1, (n/prime(A061395(n)))*prime(1+A061395(n)));
A253560(n) = if(1==n, 1, (n*prime(A061395(n))));
A253565(n) = if(n<2, (1+n), if(!(n%2), A253550(A253565(n/2)), A253560(A253565((n-1)/2)))); \\ Would be better if memoized!
write_to_bfile(0, rgs_transform(vector(65538, n, A278535(n-1))), "b286535.txt");
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, May 17 2017
STATUS
approved