A110737 Row sums in A112668.

1, 4, 21, 40, 1555, 3906, 299593, 3280, 87381, 435848050, 67546215517, 61035156, 61054982558011, 328114698808274, 76861433640456465, 21523360, 128583032925805678351, 953674316406, 275941052631578947368421, 1743392200

Offset: 1

Author

Amarnath Murthy, Aug 10 2005

Keywords

• easy
• nonn

Comments

For all n, a(n) is a term in row n of triangle A125118, and furthermore if n is prime then a(n) = A060072(n+1). - Mathew Englander, Dec 20 2020

Links

• Michael De Vlieger, Table of n, a(n) for n = 1..388

Crossrefs

Cf. A110738, A110739, A125118, A060072.

Programs

Maple

A110737 := proc(n) local i,a ; if n = 1 then RETURN(1) ; else a := 2 ; while (1-a^n)/(1-a) mod n <> 0 do a := a+1 ; od ; RETURN( (1-a^n)/(1-a) ) ; fi ; end: for n from 1 to 25 do printf("%d, ",A110737(n)) : od : # R. J. Mathar, Mar 13 2007

Mathematica

Block[{a = {1}, k, s}, Do[k = 2; While[Mod[Set[s, Total@ NestList[# k &, 1, i - 1]], i] != 0, k++]; AppendTo[a, s], {i, 2, 20}]; a] (* Michael De Vlieger, Dec 31 2020 *)

Extensions

More terms from R. J. Mathar, Mar 13 2007