A081515 Sum of terms in n-th row of A081517.

1, 3, 7, 11, 17, 23, 29, 37, 47, 59, 67, 79, 97, 107, 127, 137, 157, 173, 191, 211, 233, 257, 277, 307, 331, 353, 379, 409, 439, 467, 499, 541, 563, 599, 631, 673, 709, 743, 787, 821, 863, 907, 947, 991, 1039, 1087, 1129, 1181, 1229, 1277, 1327, 1381, 1433, 1487

Offset

1,2

Comments

a(n) is > the n-th triangular number. Conjecture: There are no composite members.

Links

Table of n, a(n) for n=1..54.

Prog

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

Crossrefs

Cf. A081516, A081517.

Sequence in context: A090513 A285600 A191050 * A289750 A184856 A023234

Adjacent sequences: A081512 A081513 A081514 * A081516 A081517 A081518

Keyword

nonn

Author

Amarnath Murthy, Mar 27 2003

Extensions

a(7)-a(9) from R. J. Mathar, Mar 23 2007

More terms from Jinyuan Wang, May 23 2020

Status

approved