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Search: id:A073606
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| A073606 |
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Smaller of two consecutive integers divisible respectively by two consecutive primes. |
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+0
8
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| 2, 8, 9, 14, 20, 21, 24, 26, 32, 38, 39, 44, 50, 54, 55, 56, 62, 68, 69, 74, 77, 80, 84, 86, 90, 92, 98, 99, 104, 110, 114, 115, 116, 122, 125, 128, 129, 134, 140, 144, 146, 152, 158, 159, 160, 164, 169, 170, 174, 175, 176, 182, 188, 189, 194, 195, 200, 204, 206
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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There are arbitrarily long strings of consecutive integers in this sequence; for example, A072562(k+1) is followed by at least k-1 more consecutive members. - David Wasserman (wasserma(AT)spawar.navy.mil), Oct 21 2004
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EXAMPLE
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54 is a term as 54 and 55 are divisible by 3 and 5 respectively. 55 is also a term as 55 and 56 are divisible by 5 and 7. 56 is also a term as 56 and 57 are divisible by 2 and 3.
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MATHEMATICA
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f[n_Integer] := Flatten[ Table[ #1] & @@@ FactorInteger[n]]; NextPrim[n_] := Block[ {k = n + 1}, While[ !PrimeQ[k], k++ ]; k]; Do[ p = f[ n ]; l = Length[ p ]; t = Table[n + i, {i, 0, 1} ]; k = 1; While[ k < l + 1 && Union[ Mod[ t, NestList[ NextPrim, p[[ k ]], 1 ]]] != {0}, k++ ]; If[ k < l + 1, Print[ n ]], {n, 2, 220} ]
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CROSSREFS
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Cf. A073755, A073607, A072555, A073754, A073756 & A072562.
Sequence in context: A081381 A166686 A064833 this_sequence A047353 A032928 A056805
Adjacent sequences: A073603 A073604 A073605 this_sequence A073607 A073608 A073609
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 04 2002
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EXTENSIONS
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Edited by Robert G. Wilson v 9rgwv(AT)rgwv.com), Aug 07 2002
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