A082773 Integers n such that there exists at least one divisor d of n, 1 < d < n, such that d divides n, d+1 divides n+1 and d+2 divides n+2.

14, 26, 38, 50, 62, 63, 64, 74, 86, 98, 110, 122, 123, 124, 134, 146, 158, 170, 174, 182, 183, 184, 194, 206, 215, 218, 230, 242, 243, 244, 254, 266, 278, 290, 302, 303, 304, 314, 326, 338, 342, 350, 362, 363, 364, 368, 374, 386, 398, 410, 422, 423, 424, 425

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

38 is in the sequence since 2 divides 38, 3 divides 39 and 4 divides 40.

Mathematica

dvsQ[n_]:=Module[{dvsrs=Rest[Most[Divisors[n]]]}, Table[Divisible[n+1, dvsrs[[i]]+1] && Divisible[n+2, dvsrs[[i]]+2], {i, Length[dvsrs]}]]; Select[Range[2, 450], !PrimeQ[#]&&Or@@dvsQ[#]&] (* Harvey P. Dale, Dec 28 2011 *)

Prog

for (int a = 1; a < 200; a++) for (int b = 2; b < a; b++) if ((a%b==0)&&((a+1)%(b+1)==0)&&((a+2)%(b+2)==0)) cout << a << ", "; // outputs a
(PARI) isok(n) = {fordiv(n, d, if ((d>1) && (d<n) && ! ((n+1) % (d+1)) && ! ((n+2) % (d+2)), return (1)); ); } \\ Michel Marcus, Sep 18 2019

Crossrefs

Sequence in context: A344872 A240227 A191992 * A242395 A112772 A155505

Adjacent sequences: A082770 A082771 A082772 * A082774 A082775 A082776

Keyword

easy,nonn

Author

Anne M. Donovan (anned3005(AT)aol.com), May 21 2003

Status

approved