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 A167147 a(n) = Number of subsets with n members of the set {1..n^2} such that the sum of the members is prime. 4
 4, 26, 444, 11998, 382716, 15844060, 766387489, 42716991304, 2704983373484, 193042233338665, 15032959574223321, 1289808484211222447, 120472472277271660102, 12036408131864572935262, 1297010265532587186011353, 151499235341042432049982767, 18434494194245279115211501310, 2430305919107872967957571237320, 334200348422242729412526022526012 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 COMMENTS The sequence was conceived by Zak Seidov. Further terms were calculated by Alois P. Heinz. LINKS Alois P. Heinz, Table of n, a(n) for n = 2..29 EXAMPLE When n=2, a(2) = 4 because there are 4 subsets of the set {1,2,3,4} with prime sums: {1,2}=>3, {1,4}=>5, {2,3}=>5, {3,4}=>7. When n=3, a(3) = 26 because there are 26 subsets of the set {1,2,3,4,5,6,7,8,9} with prime sums: {1,2,4}=>7, {1,2,8}=>11, {1,3,7}=>11, {1,3,9}=>13, {1,4,6}=>11, {1,4,8}=>13, {1,5,7}=>13, {1,7,9}=>17, {2,3,6}=>11, {2,3,8}=>13, {2,4,5}=>11, {2,4,7}=>13, {2,5,6}=>13, {2,6,9}=>17, {2,7,8}=>17, {2,8,9}=>19, {3,4,6}=>13, {3,5,9}=>17, {3,6,8}=>17, {3,7,9}=>19, {4,5,8}=>17, {4,6,7}=>17, {4,6,9}=>19, {4,7,8}=>19, {5,6,8}=>19, {6,8,9}=>23. MAPLE g:= proc(n, i, t) option remember;       if n<0 or t<0 then 0     elif n=0 then `if`(t=0, 1, 0)     elif i<1 or i

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Last modified June 17 19:10 EDT 2019. Contains 324198 sequences. (Running on oeis4.)