A198293 a(n) = (1/n)*A205406(n).

1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 3

Offset

1,9

Comments

For a guide to related sequences, see A204892.

Links

Paolo Xausa, Table of n, a(n) for n = 1..20000

Mathematica

(See the program at A205402.)
s[m_]:=s[m]=Floor[(m+1)^2/2]/2
A205406[n_]:=(k=2; found=False; While[!found, Do[If[Mod[d=s[k]-s[j], n]==0, found=True; Break[]], {j, k-1}]; k++]; d)
nterms=100; Table[A205406[n]/n, {n, nterms}] (* Paolo Xausa, Dec 03 2021 *)

Prog

(PARI)
A002620(n) = ((n^2)>>2);
A002620shiftedleft(n) = A002620(1+n);
A205406(n) = { my(d); for(k=2, oo, for(j=1, k-1, if(!((d=A002620shiftedleft(k)-A002620shiftedleft(j))%n), return(d)))); };
A198293(n) = (A205406(n)/n); \\ Antti Karttunen, Dec 03 2021

Crossrefs

Cf. A002620, A205402, A205406, A204892.

Sequence in context: A160322 A375667 A341644 * A368330 A043281 A365634

Adjacent sequences: A198290 A198291 A198292 * A198294 A198295 A198296

Keyword

nonn

Author

Clark Kimberling, Jan 27 2012

Extensions

Data section extended up to a(111) by Antti Karttunen, Dec 03 2021

Status

approved