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A112422 Number of 6-element subsets of {1,2,3,...,n} for which the sum-set has 13 elements. 1
3, 11, 19, 27, 35, 43, 54, 65, 81, 97, 113, 129, 148, 167, 186, 210, 234, 258, 285, 312, 339, 366, 398, 430, 465, 500, 535, 570, 605, 645, 688, 731, 774, 817, 860, 903, 954, 1005, 1056, 1107, 1158, 1209, 1263, 1322, 1381, 1440, 1499, 1558, 1620, 1682, 1749 (list; graph; refs; listen; history; text; internal format)
OFFSET

7,1

LINKS

Colin Barker, Table of n, a(n) for n = 7..1000

Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,1,0,-1,0,0,0,0,-1,1).

FORMULA

G.f.: x^7*(3 +8*x +8*x^2 +8*x^3 +8*x^4 +8*x^5 +8*x^6) / ((1 -x)^3*(1 +x)*(1 -x +x^2)*(1 +x +x^2)*(1 +x +x^2 +x^3 +x^4 +x^5 +x^6)). - Corrected by Colin Barker, Jan 10 2017

MATHEMATICA

LinearRecurrence[{1, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, -1, 1}, {3, 11, 19, 27, 35, 43, 54, 65, 81, 97, 113, 129, 148, 167}, 60] (* Harvey P. Dale, Jul 01 2020 *)

PROG

(PARI) Vec(x^7*(3 +8*x +8*x^2 +8*x^3 +8*x^4 +8*x^5 +8*x^6) / ((1 -x)^3*(1 +x)*(1 -x +x^2)*(1 +x +x^2)*(1 +x +x^2 +x^3 +x^4 +x^5 +x^6)) + O(x^60)) \\ Colin Barker, Jan 10 2017

CROSSREFS

Sequence in context: A043433 A078583 A017101 * A289840 A125994 A137295

Adjacent sequences:  A112419 A112420 A112421 * A112423 A112424 A112425

KEYWORD

nonn,easy

AUTHOR

David S. Newman, Dec 10 2005

EXTENSIONS

Edited by Colin Barker, Jan 10 2017

STATUS

approved

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Last modified September 29 12:15 EDT 2020. Contains 337431 sequences. (Running on oeis4.)