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A220505
a(n) = spt(5n+4)/5 where spt(n) = A092269(n).
3
2, 16, 88, 364, 1309, 4126, 11992, 32368, 82590, 200487, 467152, 1049224, 2283364, 4829302, 9959035, 20069790, 39612612, 76703340, 145945332, 273224940, 503888206, 916373028, 1644925432, 2916814954, 5113148026, 8866911378, 15220453704
OFFSET
0,1
COMMENTS
That spt(5n+4) == 0 (mod 5) is one of the congruences stated by George E. Andrews. See theorem 2 in the Andrews' paper. See also A220507 and A220513.
FORMULA
a(n) = A092269(A016897(n))/5 = A220485(n)/5.
MATHEMATICA
b[n_, i_] := b[n, i] = If[n==0 || i==1, n, {q, r} = QuotientRemainder[n, i]; If[r == 0, q, 0] + Sum[b[n - i j, i - 1], {j, 0, n/i}]];
spt[n_] := b[n, n];
a[n_] := spt[5n+4]/5;
Table[a[n], {n, 0, 26}] (* Jean-François Alcover, Jan 30 2019, after Alois P. Heinz in A092269 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Jan 18 2013
STATUS
approved