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A174655 Partial sums of A049486. 1
1, 5, 15, 36, 70, 123, 197, 298, 428, 593, 795, 1040, 1330, 1671, 2065, 2518, 3032, 3613, 4263, 4988, 5790, 6675, 7645, 8706, 9860, 11113, 12467, 13928, 15498, 17183, 18985, 20910, 22960, 25141, 27455, 29908, 32502, 35243, 38133, 41178, 44380 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Partial sums of maximum length of non-crossing path on n X n square lattice. The subsequence of primes in this partial sum begins: 5, 197, 593, 3613, 11113, 17183.
LINKS
FORMULA
a(n) = SUM[i=1..n] A049486(i).
Conjecture: a(n) = (3*(-9+(-1)^n)+34*n-12*n^2+8*n^3)/12 for n>1. G.f.: x*(x^5-x^4+3*x^3+2*x^2+2*x+1) / ((x-1)^4*(x+1)). - Colin Barker, May 02 2013
EXAMPLE
a(7) = 1 + 4 + 10 + 21 + 34 + 53 + 74 = 197 is prime.
MATHEMATICA
Accumulate[Join[{1, 4}, LinearRecurrence[{2, 0, -2, 1}, {10, 21, 34, 53}, 40]]] (* or *) Join[{1, 5}, LinearRecurrence[{3, -2, -2, 3, -1}, {15, 36, 70, 123, 197}, 40]] (* Harvey P. Dale, Aug 21 2013 *)
CROSSREFS
Sequence in context: A065780 A220480 A105720 * A184631 A366971 A011933
KEYWORD
nonn
AUTHOR
Jonathan Vos Post, Mar 25 2010
STATUS
approved

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Last modified April 21 10:17 EDT 2024. Contains 371852 sequences. (Running on oeis4.)