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A059400
a(n) is the least odd number of the form p + k^2 with p prime and k > 0 which can be represented in exactly n different ways.
1
1, 3, 11, 27, 77, 83, 167, 293, 227, 503, 437, 887, 923, 1007, 1133, 1487, 2243, 2147, 2477, 2273, 2537, 3167, 3947, 4457, 4703, 3737, 3713, 5843, 6233, 8123, 8333, 5297, 11513, 10127, 9407, 10853, 10577, 13187, 8153, 12473, 8777, 15923, 16463, 17513
OFFSET
0,2
COMMENTS
Note that A002471 allows for k to equal zero.
REFERENCES
David Wells, "The Penguin Dictionary of Curious and Interesting Numbers," Revised Edition, Penguin Books, London, 1997, page 63.
LINKS
EXAMPLE
a(3) = 27 because 27 = 23+2^2 = 11+4^2 = 2+5^2 and is the least odd number to exhibit this property of 3 representations.
MATHEMATICA
a = Table[ 0, {55} ]; Do[ c = 0; k = 1; While[ n - k^2 > 1, If[ PrimeQ[ n - k^2], c++ ]; k++ ]; If[ a[[c]] == 0, a[[c]] = n], { n, 1, 30500, 2} ]; a
CROSSREFS
Cf. A002471.
Sequence in context: A147118 A147157 A146826 * A250223 A250271 A289842
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Mar 15 2001
EXTENSIONS
Name clarified by Donovan Johnson, Nov 24 2012
STATUS
approved