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A045967
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a(1)=4; if n = Product p_i^e_i, n > 1, then a(n) = Product p_{i+1}^{e_i+1}.
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5
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4, 9, 25, 27, 49, 225, 121, 81, 125, 441, 169, 675, 289, 1089, 1225, 243, 361, 1125, 529, 1323, 3025, 1521, 841, 2025, 343, 2601, 625, 3267, 961, 11025, 1369, 729, 4225, 3249, 5929, 3375, 1681, 4761, 7225, 3969, 1849, 27225, 2209, 4563, 6125, 7569, 2809, 6075
(list;
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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REFERENCES
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From a puzzle proposed by Marc LeBrun.
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LINKS
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Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
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MATHEMATICA
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a[1]=4; a[n_] := Thread[f = FactorInteger[n]; Times @@ Power[f[[All, 1]] // NextPrime , f[[All, 2]] + 1]]; Array[a, 50] (* Jean-François Alcover, Feb 03 2015 *)
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PROG
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(Haskell)
a045967 1 = 4
a045967 n = product $ zipWith (^)
(map a151800 $ a027748_row n) (map (+ 1) $ a124010_row n)
-- Reinhard Zumkeller, Jun 03 2013, Dec 23 2011
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CROSSREFS
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Cf. A045966, A027748, A124010, A000040.
Cf. A151800.
Sequence in context: A126638 A340640 A073045 * A336445 A232241 A163836
Adjacent sequences: A045964 A045965 A045966 * A045968 A045969 A045970
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KEYWORD
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easy,nonn,nice
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AUTHOR
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N. J. A. Sloane
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EXTENSIONS
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More terms from David W. Wilson
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STATUS
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approved
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