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A084112
Nonprimes in A084111.
2
1, 16, 48, 80, 81, 112, 405, 567, 625, 704, 832, 891, 1053, 1088, 1216, 1377, 1472, 1539, 1856, 1863, 1984, 2368, 2401, 2624, 2752, 3008, 3392, 3776, 3904, 4032, 4288, 4375, 4544, 4672, 5056, 5312, 5696, 6208, 6464, 6592, 6848, 6875, 6976, 7232, 8125
OFFSET
1,2
COMMENTS
A084110(a(n)) = a(n) and A010051(a(n)) = 0.
LINKS
EXAMPLE
All terms < 10000, and their prime factorizations:
. n | a(n) | . n | a(n) |
. ---+-------+----------- . ---+-------+---------------
. 1 | 1 | 1 . 27 | 3392 | 2^6 * 53
. 2 | 16 | 2^4 . 28 | 3776 | 2^6 * 59
. 3 | 48 | 2^4 * 3 . 29 | 3904 | 2^6 * 61
. 4 | 80 | 2^4 * 5 . 30 | 4032 | 2^6 * 3^2 * 7
. 5 | 81 | 3^4 . 31 | 4288 | 2^6 * 67
. 6 | 112 | 2^4 * 7 . 32 | 4375 | 5^4 * 7
. 7 | 405 | 3^4 * 5 . 33 | 4544 | 2^6 * 71
. 8 | 567 | 3^4 * 7 . 34 | 4672 | 2^6 * 73
. 9 | 625 | 5^4 . 35 | 5056 | 2^6 * 79
. 10 | 704 | 2^6 * 11 . 36 | 5312 | 2^6 * 83
. 11 | 832 | 2^6 * 13 . 37 | 5696 | 2^6 * 89
. 12 | 891 | 3^4 * 11 . 38 | 6208 | 2^6 * 97
. 13 | 1053 | 3^4 * 13 . 39 | 6464 | 2^6 * 101
. 14 | 1088 | 2^6 * 17 . 40 | 6592 | 2^6 * 103
. 15 | 1216 | 2^6 * 19 . 41 | 6848 | 2^6 * 107
. 16 | 1377 | 3^4 * 17 . 42 | 6875 | 5^4 * 11
. 17 | 1472 | 2^6 * 23 . 43 | 6976 | 2^6 * 109
. 18 | 1539 | 3^4 * 19 . 44 | 7232 | 2^6 * 113
. 19 | 1856 | 2^6 * 29 . 45 | 8125 | 5^4 * 13
. 20 | 1863 | 3^4 * 23 . 46 | 8128 | 2^6 * 127
. 21 | 1984 | 2^6 * 31 . 47 | 8192 | 2^13
. 22 | 2368 | 2^6 * 37 . 48 | 8384 | 2^6 * 131
. 23 | 2401 | 7^4 . 49 | 8768 | 2^6 * 137
. 24 | 2624 | 2^6 * 41 . 50 | 8896 | 2^6 * 139
. 25 | 2752 | 2^6 * 43 . 51 | 9536 | 2^6 * 149
. 26 | 3008 | 2^6 * 47 . 52 | 9664 | 2^6 * 151 .
PROG
(PARI) f(n) = local(d, m); d = divisors(n); m = 1; for (i = 2, length(d), if (m%d[i], m *= d[i], m = m/d[i])); m; count = 0; i = 0; while (count < 70, i++; if (!isprime(i), if (f(i) == i, count++; print(i)))); \\ David Wasserman, Dec 13 2004
(Haskell)
a084112 n = a084112_list !! (n-1)
a084112_list = filter ((== 0) . a010051') a084111_list
-- Reinhard Zumkeller, Jul 31 2014
CROSSREFS
Subsequence of A084111.
Sequence in context: A374589 A336595 A069084 * A050428 A134605 A035008
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, May 12 2003
EXTENSIONS
More terms from David Wasserman, Dec 13 2004
STATUS
approved