A205032 a(n) = (s(k)-s(j))/n, where (s(k),s(j)) is the least pair of oblong numbers (A002378) for which n divides their difference; a(n) = (1/n)*A205031(n).

4, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2

Offset: 1

Author

Clark Kimberling, Jan 22 2012

Keywords

• nonn

Comments

For a guide to related sequences, see A204892.

Even n such that a(n) = 2 are: 2, 12, 20, 56, 72, 132, 156, 240, 272, 380, 552, 812, 992, 1056, 1332, 1640, 1892, 2256, 2756, 3540, 3660, 4032, 4160, 4556, 5112, 5256, 6320, 6972, 7656, 7832, ... - Antti Karttunen, Nov 06 2018

Links

• Antti Karttunen, Table of n, a(n) for n = 1..14025

Crossrefs

Cf. A002378, A205018, A205031, A204892.

Cf. also A204897, A204999, A205007.

Programs

Mathematica

(See the program at A205018.)

PARI

A205032(n) = for(k=2,oo,my(sk=k*(k+1)); for(j=1,k-1,if(!((sk-((j+1)*j))%n),return((sk-((j+1)*j))/n)))); \\ Antti Karttunen, Nov 06 2018

PARI

A205032(n) = for(k=sqrtint(n)-1,oo,my(sk=k*(k+1), d); for(j=1,k-1,d=(sk-((j+1)*j)); if(0==(d%n),return(d/n),if(dAntti Karttunen, Nov 06 2018

Extensions

Definition edited and more terms from Antti Karttunen, Nov 06 2018