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Search: id:A062090
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| A062090 |
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a(1) = 1, a(n)= smallest odd number which does not divide the product of all previous terms. |
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+0
8
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| 1, 3, 5, 7, 9, 11, 13, 17, 19, 23, 25, 29, 31, 37, 41, 43, 47, 49, 53, 59, 61, 67, 71, 73, 79, 81, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 137, 139, 149, 151, 157, 163, 167, 169, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 289, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 361, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 529, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 625, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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In A050150 but not here: [729, 15625, 59049, 117649, 531441]; here but not in A050150: [1, 6561, 390625]. - Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Nov 01, 2001
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..1000
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FORMULA
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Numbers of the form p^(2^k) where p is an odd prime and k is a nonnegative integer.
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EXAMPLE
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After 13 the next term is 17 (not 15) as 15 = 3*5 divides the product of all the previous terms.
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MATHEMATICA
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a = {1}; Do[b = Apply[ Times, a]; k = 1; While[ IntegerQ[b/k], k += 2]; a = Append[a, k], { n, 2, 60} ]; a
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CROSSREFS
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Cf. A026477, A062091, A050150 (a different sequence).
Sequence in context: A061345 A080429 A050150 this_sequence A133854 A030155 A143448
Adjacent sequences: A062087 A062088 A062089 this_sequence A062091 A062092 A062093
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KEYWORD
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nonn,easy,nice
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jun 16 2001
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EXTENSIONS
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Corrected and extended by Dean Hickerson (dean.hickerson(AT)yahoo.com), Jul 10, 2001
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