cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A060339 Primes that are each the sum of two, three, and four consecutive composite numbers.

Original entry on oeis.org

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

Views

Author

Robert G. Wilson v, Mar 30 2001

Keywords

Examples

			A(2)= 377 is equal to 168+169 = 111+112+114 = 82+84+85+86.
		

Crossrefs

Cf. A151744. [From Klaus Brockhaus, Jun 17 2009]

Programs

  • 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