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A333011
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Integers which can be written in only one way as a sum of two distinct nonzero pentagonal numbers.
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5
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6, 13, 17, 23, 27, 34, 36, 40, 47, 52, 56, 57, 63, 71, 73, 75, 82, 86, 92, 93, 97, 104, 105, 114, 118, 121, 122, 127, 129, 139, 143, 146, 150, 152, 157, 162, 167, 168, 177, 180, 181, 187, 188, 196, 198, 209, 222, 227, 232, 237, 245, 246, 248, 252, 259, 261, 262
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OFFSET
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1,1
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COMMENTS
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The first term of A332988 not in this sequence is 211.
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LINKS
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PROG
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(PARI) is(k) = sum(i=1, sqrt(1+12*k)\6, sqrt(1+24*k+12*i-36*i*i)%6==5) == 1; \\ Jinyuan Wang, Mar 06 2020
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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