A125668 - OEIS

A125668

Numbers not expressible as the sum of a triangular number and an abundant number.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 14, 16, 17, 29, 32, 38, 44, 47, 53, 74, 137, 152, 164, 194, 284, 662

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OFFSET

1,2

LINKS

Jason Earls and Jason Rogers, "I Sin Every Number", If{Sid_Vicious == TRUE && Alan_Turing == TRUE, ERROR_Cyberpunk();} (title of book), Lulu Press, NY, 2007, p. 49.

MATHEMATICA

lim=700; tlim=Floor[Sqrt[2lim]]; t=Accumulate[Range[0, tlim]]; a=Select[Range[lim], DivisorSigma[1, #] > 2 # &] ; la=Length[a]; s={}; Do[AppendTo[s, t[[i]]+a[[j]]], {i, tlim}, {j, la}]; Complement[Range[700], s] (* James C. McMahon, Dec 19 2024 *)

CROSSREFS

Cf. A000217, A005101.

Sequence in context: A252494 A393773 A030294 * A365472 A034894 A263564

Adjacent sequences: A125665 A125666 A125667 * A125669 A125670 A125671

KEYWORD

easy,fini,nonn

AUTHOR

Jason Earls, Jan 29 2007

STATUS

approved