A272266 The union of squares (A000290) and 10-gonal numbers (A001107).

1, 4, 9, 10, 16, 25, 27, 36, 49, 52, 64, 81, 85, 100, 121, 126, 144, 169, 175, 196, 225, 232, 256, 289, 297, 324, 361, 370, 400, 441, 451, 484, 529, 540, 576, 625, 637, 676, 729, 742, 784, 841, 855, 900, 961, 976, 1024, 1089, 1105, 1156, 1225, 1242, 1296

Offset

1,2

Links

Colin Barker, Table of n, a(n) for n = 1..1000

Formula

Conjectures:

a(n) = a(n-1)+2*a(n-3)-2*a(n-4)-a(n-6)+a(n-7) for n>7.

G.f. x*(1+3*x+5*x^2-x^3-x^5+x^6) / ((1-x)^3*(1+x+x^2)^2).

Prog

(PARI)
pg(m, n) = (n^2*(m-2)-n*(m-4))/2 \\ The n-th m-gonal number
pgr(m, r) = n=1; L=List(); while((t=pg(m, n))<r, listput(L, t); n++); Vec(L)
pgpgs(p, q, r) = setunion(pgr(p, r), pgr(q, r))
pgpgs(4, 10, 2000)

Crossrefs

Cf. A000290, A001107, A272267.

Sequence in context: A243188 A117570 A337816 * A155566 A305231 A312832

Adjacent sequences: A272263 A272264 A272265 * A272267 A272268 A272269

Keyword

nonn

Author

Colin Barker, Apr 24 2016

Status

approved