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A220507
a(n) = spt(7n+5)/7 where spt(n) = A092269(n).
3
2, 34, 260, 1498, 6956, 28024, 100953, 333680, 1026540, 2976024, 8197962, 21608760, 54788100, 134217717, 318816426, 736549424, 1659169712, 3652248590, 7870890952, 16633964444, 34522173765, 70450341042, 141526909340, 280158178412
OFFSET
0,1
COMMENTS
That spt(7n+5) == 0 (mod 7) is one of the congruences stated by George E. Andrews. See theorem 2 in the Andrews' paper. See also A220505 and A220513.
FORMULA
a(n) = A092269(A017041(n))/7 = A220502(n)/7.
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[7 n + 5]/7;
Table[a[n], {n, 0, 23}] (* Jean-François Alcover, Jan 30 2019, after Alois P. Heinz in A092269 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Jan 18 2013
STATUS
approved