A060339 Primes that are each the sum of two, three, and four consecutive composite numbers.
311, 337, 1009, 1103, 1511, 1777, 3671, 3889, 4271, 4657, 5737, 6841, 7561, 9649, 9769, 10223, 12239, 12889, 14759, 14831, 17401, 17569, 17783, 19009, 19031, 20903, 21529, 22369, 22751, 23279, 24049, 24889, 25057, 26423, 28871, 30671
Offset: 1
Keywords
Examples
A(2)= 377 is equal to 168+169 = 111+112+114 = 82+84+85+86.
Links
- Klaus Brockhaus, Table of n, a(n) for n=1..1000. [From _Klaus Brockhaus_, Jun 17 2009]
Crossrefs
Cf. A151744. [From Klaus Brockhaus, Jun 17 2009]
Programs
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Mathematica
composite[ n_Integer ] := (k = n + PrimePi[ n ] + 1; While[ k - PrimePi[ k ] - 1 != n, k++ ]; k); a = b = c = {}; Do[ p = Sum[ composite[ n + m ], {m, 0, 1} ]; If[ PrimeQ[ p ], a = Append[ a, p ] ]; p = Sum[ composite[ n + m ], {m, 0, 2} ]; If[ PrimeQ[ p ], b = Append[ b, p ] ]; p = Sum[ composite[ n + m ], {m, 0, 3} ]; If[ PrimeQ[ p ], c = Append[ c, p ] ], {n, 1, 25000} ]; Intersection[ a, b, c ] Module[{cmp=Select[Range[20000],CompositeQ],c2,c3,c4},c2=Total/@ Partition[ cmp,2,1];c3=Total/@Partition[cmp,3,1];c4=Total/@ Partition[ cmp,4,1];Select[ Intersection[c2,c3,c4],PrimeQ]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 01 2020 *)
Extensions
Definition clarified by Harvey P. Dale, Jul 01 2020