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A081491 Triangle read by rows in which the n-th row contains n terms of an arithmetic progression with a common difference of (n-1) and the first term of (n+1)-th row is 1 more than the last term of the n-th row. 4

%I #13 Feb 14 2024 12:29:12

%S 1,2,3,4,6,8,9,12,15,18,19,23,27,31,35,36,41,46,51,56,61,62,68,74,80,

%T 86,92,98,99,106,113,120,127,134,141,148,149,157,165,173,181,189,197,

%U 205,213,214,223,232,241,250,259,268,277,286,295,296,306,316,326,336,346

%N Triangle read by rows in which the n-th row contains n terms of an arithmetic progression with a common difference of (n-1) and the first term of (n+1)-th row is 1 more than the last term of the n-th row.

%H Harvey P. Dale, <a href="/A081491/b081491.txt">Table of n, a(n) for n = 1..10000</a>

%e 1; 2,3; 4,6,8; 9,12,15,18; 19,23,27,31,35; 36,41,46,51,56,61; ...

%t Table[NestList[#+n-1&,(2n^3-9n^2+19n-6)/6,n-1],{n,11}]//Flatten (* _Harvey P. Dale_, Feb 12 2024 *)

%Y Cf. A002522, A005408, A081489, A081490, A081492.

%K nonn,tabl

%O 1,2

%A _Amarnath Murthy_, Mar 25 2003

%E More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 29 2003

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Last modified September 2 22:46 EDT 2024. Contains 375620 sequences. (Running on oeis4.)