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A217512 Partial sums of nonzero terms in A005925. 4
1, 5, 17, 29, 35, 47, 71, 87, 99, 123, 147, 159, 167, 191, 239, 275, 281, 293, 329, 357, 381, 417, 441, 465, 489, 525, 597, 633, 657, 705, 729, 741, 801, 849, 885, 915, 943, 1015, 1063, 1087, 1099, 1147, 1207, 1231, 1291, 1339, 1363, 1371, 1419, 1503, 1551 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Sizes of clusters of atoms in diamond structure.

REFERENCES

N. J. A. Sloane, Theta-Series and Magic Numbers for Diamond and Certain Ionic Crystal Structures, J. Math. Phys., 28 (1987), pp. 1653-1657.

LINKS

Table of n, a(n) for n=0..50.

PROG

(PARI) lista(m) = {nm = sqrtint(m)+1; T2 = sum(i=0, nm, 2*x^((i+1/2)^2 - 1/4)); T23 = T2^3; T3 = 1+ sum(i=1, nm, 2*x^(i^2)); T4 = subst(T3, x, -x); T33 = T3^3; T334 = sum(i=0, m, polcoeff(T33, i)*x^(4*i)); T43 = T4^3; T434 = sum(i=0, m, polcoeff(T43, i)*x^(4*i)); P = sum(i=0, poldegree(T23), polcoeff(T23, i)*x^(numerator(i+3/4))); D = (P + T334 + T434)/2; s = 0; for (i=0, m, v = polcoeff(D, i); if (v != 0, s += v; print1(s, ", "); ); ); } \\ Michel Marcus, Feb 19 2013

CROSSREFS

Cf. A005925-A005927, A217512-A217514.

Sequence in context: A195032 A264618 A271471 * A289836 A068829 A090403

Adjacent sequences:  A217509 A217510 A217511 * A217513 A217514 A217515

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Oct 05 2012

EXTENSIONS

More terms from Michel Marcus, Feb 19 2013

STATUS

approved

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Last modified May 26 10:11 EDT 2019. Contains 323579 sequences. (Running on oeis4.)