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A114871
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Numbers of the form (p-1)p^k (where p is a prime and k>=0) in ascending order.
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7
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1, 2, 4, 6, 8, 10, 12, 16, 18, 20, 22, 28, 30, 32, 36, 40, 42, 46, 52, 54, 58, 60, 64, 66, 70, 72, 78, 82, 88, 96, 100, 102, 106, 108, 110, 112, 126, 128, 130, 136, 138, 148, 150, 156, 162, 166, 172, 178, 180, 190, 192, 196, 198, 210, 222, 226, 228, 232, 238, 240, 250
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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COMMENTS
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These numbers play a crucial role in inverting Euler's totient function.
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LINKS
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EXAMPLE
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18 is an element of the sequence because 18=(3-1)3^2 and 3 is a prime.
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MAPLE
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N:= 1000: # for terms <= N
S:= {}: R:= NULL:
p:= 1:
while p <= N do
p:= nextprime(p);
S:= S union {seq((p-1)*p^k, k = 0..ilog[p](N/(p-1)))};
R:= R, seq((p-1)*p^k, k = 0..ilog[p](N/(p-1)))
od:
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MATHEMATICA
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Take[Union@ Flatten@ Table[(Prime[n] - 1)Prime[n]^k, {n, 60}, {k, 0, 7}], 61] (* Robert G. Wilson v, Jan 05 2006 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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