A103263 Number of partitions of n into distinct parts prime to 3 and 5.
1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 4, 5, 5, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 17, 18, 20, 22, 25, 28, 30, 33, 36, 39, 43, 48, 52, 56, 61, 67, 73, 80, 87, 94, 101, 110, 120, 130, 141, 152, 164, 177, 192, 207, 223, 240, 258, 278, 301, 324, 348, 373, 400, 429, 461, 496
Offset: 0
Examples
E.g. a(15)=5 because we can write 15 as 14+1=13+2=11+4=8+7=8+4+2+1.
Programs
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Maple
series(product((1+x^k)*(1+x^(15*k))/((1+x^(3*k))*(1+x^(5*k))),k=1..100),x=0,100);
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Mathematica
CoefficientList[ Series[ Product[(1 + x^k)(1 + x^(15*k))/((1 + x^(3k))*(1 + x^(5k))), {k, 100}], {x, 0, 75}], x] (* Robert G. Wilson v, Feb 22 2005 *) -
PARI
{a(n)=local(A); if (n<0, 0, A=x*O(x^n); polcoeff( eta(x^2+A)*eta(x^3+A)*eta(x^5+A)*eta(x^30+A)/ (eta(x+A)*eta(x^6+A)*eta(x^10+A)*eta(x^15+A)), n))} /* Michael Somos, Sep 22 2005 */
Formula
Expansion of q^(-1/3)(eta(q^2)*eta(q^3)*eta(q^5)*eta(q^30))/(eta(q)*eta(q^6)*eta(q^10)*eta(q^15)) in powers of q. - Michael Somos, Sep 22 2005.
G.f.: product_{k>0}((1+x^k)*(1+x^(15k)))/((1+x^(3k))*(1+x^(5k))).
Euler transform of period 30 sequence [1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, ...]. - Michael Somos, Sep 22 2005
Given g.f. A(x), then B(x)=x*A(x^3) satisfies 0=f(B(x), B(x^2)) where f(u, v)=u*(u-v^2)^2 +v*(v-u^2)^2 -u*v -(u*v)^3. - Michael Somos, Sep 22 2005
Given g.f. A(x), then B(x)=x*A(x^3) satisfies 0=f(B(x), B(x^2), B(x^4)) where f(u, v, w)=(v+u*w)^2 -v*(u^2+w^2). - Michael Somos, Sep 22 2005
G.f.: Product_{k>0} (1+x^k-x^(3k)-x^(4k)-x^(5k)+x^(7k)+x^(8k)). - Michael Somos Sep 22 2005
a(n) ~ exp(2*Pi*sqrt(2*n/5)/3) / (2^(3/4) * sqrt(3) * 5^(1/4) * n^(3/4)). - Vaclav Kotesovec, Sep 06 2015
Extensions
More terms from Robert G. Wilson v, Feb 22 2005