login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A081523 Sum of terms in row n of A081521. 3
1, 4, 12, 16, 20, 54, 35, 64, 72, 130, 77 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..11.

PROG

(PARI) a(n) = {my(m=n*(n-1)/2, v); forstep(k=m+n/(2-n%2), oo, n, v=List([]); for(i=2, k-m, if(gcd(n, i)==1, listput(v, i))); if(#v>n-2, forsubset([#v, n-1], w, if(r=1+sum(i=1, n-1, v[w[i]])==k, return(k))))); } \\ Jinyuan Wang, May 23 2020

CROSSREFS

Cf. A081521, A081522, A081524.

Sequence in context: A077770 A310566 A108269 * A310567 A310568 A257692

Adjacent sequences:  A081520 A081521 A081522 * A081524 A081525 A081526

KEYWORD

nonn,more

AUTHOR

Amarnath Murthy, Mar 27 2003

EXTENSIONS

a(8)-a(11) from Jinyuan Wang, May 23 2020

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 23 12:19 EDT 2021. Contains 346259 sequences. (Running on oeis4.)