

A084336


a(n) is the smallest composite number not already in the sequence such that the absolute values of the successive differences are distinct primes.


0



4, 6, 9, 14, 21, 8, 25, 36, 55, 12, 35, 64, 27, 58, 99, 10, 57, 110, 39, 98, 15, 76, 143, 16, 95, 22, 119, 18, 121, 228, 49, 158, 45, 176, 315, 32, 169, 20, 171, 328, 51, 214, 33, 200, 391, 24, 217, 44, 243, 46, 273, 34, 245, 468, 85, 314, 63, 296, 537, 28, 285, 548, 69
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OFFSET

0,1


COMMENTS

The absolute values of the successive difference are 2, 3, 5, 7, 13, 17, 11, 19, 43, 23, 29, 37, 31, ...
Does every composite number occur in the sequence? Does every prime occur as a difference?


LINKS



MATHEMATICA

a[0]=4; a[n_] := a[n]=Module[{x, d}, For[x=6, True, x++, If[ !PrimeQ[x]&&PrimeQ[d=Abs[xa[n1]]]&&!MemberQ[a/@Range[n1], x]&&!MemberQ[Table[Abs[a[i+1]a[i]], {i, 0, n2}], d], Return[x]]]]


CROSSREFS



KEYWORD

nonn


AUTHOR

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), Jun 18 2003


EXTENSIONS



STATUS

approved



