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A124920 Location of record values in A080577; also partial sums of A006128 plus 1. 2

%I #17 May 19 2018 12:35:50

%S 1,2,5,11,23,43,78,132,218,346,538,813,1212,1768,2548,3616,5079,7044,

%T 9688,13186,17816,23868,31767,41973,55147,71998,93520,120814,155359,

%U 198812,253375,321510,406437,511803,642265,803141,1001155,1243967

%N Location of record values in A080577; also partial sums of A006128 plus 1.

%H Vaclav Kotesovec, <a href="/A124920/b124920.txt">Table of n, a(n) for n = 1..10000</a>

%F A124920(n) = A124920(n-1)+ A006128(n-1), n>1; a(1) = 1.

%F G.f.: x/(1 - x) + Sum_{i>=1} i*x^(i+1)/(1 - x) * Product_{j=1..i} 1/(1 - x^j). - _Ilya Gutkovskiy_, Apr 04 2017

%F a(n) ~ exp(Pi*sqrt(2*n/3)) * (log(6*n) + 2*gamma - 2*log(Pi)) * sqrt(3) / (4*Pi^2), where gamma is the Euler-Mascheroni constant (A001620). - _Vaclav Kotesovec_, May 19 2018

%e A080577 begins

%e 1

%e 2 11

%e 3 21 111

%e 4 31 22 211 1111

%e 5 41 32 311 221 2111 11111

%e 6 51 42 411 33 321 3111 222 2211 21111 111111

%e therefore A124920 begins 1 2 5 11 23 ...

%p A008284 := proc(n,k) if n >= 1 and n = k or k = 1 then 1 elif k > n then 0 else add( A008284(n-k,i),i=1..k) ; fi ; end: A006128 := proc(n) add( k*A008284(n,k),k=1..n) ; end: a := 1 : printf("%d,",a) ; for n from 2 to 80 do a := a + A006128(n-1) : printf("%d,",a) ; od : # _R. J. Mathar_, Jan 13 2007

%Y Cf. A000041, A006128, A080577.

%K easy,nonn

%O 1,2

%A _Alford Arnold_, Nov 13 2006

%E More terms from _R. J. Mathar_, Jan 13 2007

%E Clarification of name from _Ilya Gutkovskiy_, Apr 04 2017

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Last modified April 25 10:22 EDT 2024. Contains 371967 sequences. (Running on oeis4.)