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 A285100 Numbers n for which A065642(n) = A285109(n). 4
 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 41, 42, 43, 44, 46, 47, 49, 51, 52, 53, 55, 57, 58, 59, 61, 62, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 76, 77, 78, 79, 81, 82, 83, 85, 86, 87, 88, 89, 91, 92, 93, 94, 95, 97, 99, 101 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Antti Karttunen, Table of n, a(n) for n = 1..10000 PROG (PARI) A020639(n) = if(1==n, n, vecmin(factor(n)[, 1])); A007947(n) = factorback(factorint(n)[, 1]); \\ From Andrew Lelechenko, May 09 2014 A065642(n) = { my(r=A007947(n)); if(1==n, n, n = n+r; while(A007947(n) <> r, n = n+r); n); }; isA285100(n) = (A065642(n) == n*A020639(n)); n=0; k=1; while(k <= 10000, n=n+1; if(isA285100(n), write("b285100.txt", k, " ", n); k=k+1)); (Scheme, with Antti Karttunen's IntSeq-library) (define A285100 (MATCHING-POS 1 1 (lambda (n) (= (A065642 n) (A285109 n))))) (Python) from operator import mul from sympy import primefactors from functools import reduce def a007947(n): return 1 if n<2 else reduce(mul, primefactors(n)) def a020639(n): return 1 if n==1 else primefactors(n)[0] def a065642(n): if n==1: return 1 r=a007947(n) n += r while a007947(n)!=r: n+=r return n print([n for n in range(1, 102) if a065642(n) == n*a020639(n)]) # Indranil Ghosh, May 24 2017 CROSSREFS Complement: A284342. Positions of ones in A285337. Subsequences: A000961, A005117. Cf. A065642, A285109. Sequence in context: A107909 A357758 A255724 * A360553 A067340 A263837 Adjacent sequences: A285097 A285098 A285099 * A285101 A285102 A285103 KEYWORD nonn AUTHOR Antti Karttunen, Apr 19 2017 STATUS approved

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Last modified June 4 21:13 EDT 2023. Contains 363130 sequences. (Running on oeis4.)