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A004797 Convolution of A002024 with itself. 1
1, 4, 8, 14, 22, 30, 41, 54, 67, 82, 99, 118, 138, 160, 182, 206, 234, 262, 292, 322, 353, 388, 425, 462, 501, 542, 583, 626, 671, 718, 766, 818, 870, 922, 976, 1030, 1088, 1148, 1210, 1274, 1338, 1402, 1469, 1538, 1607, 1678, 1753, 1828, 1905, 1984, 2063 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

Raphael Schumacher, The self-counting identity, Fib. Quart., 55 (No. 2 2017), 157-167.

LINKS

Robert Israel, Table of n, a(n) for n = 0..10000

FORMULA

G.f.: (1/(1 - x)^2)*Product_{k>=1} (1 - x^(2*k))^2/(1 - x^(2*k-1))^2 . - Ilya Gutkovskiy, May 30 2017

MAPLE

a002024:= [seq(i$i, i=1..10)]:

g002024:= add(a002024[i]*x^(i-1), i=1..nops(a002024)):

g:= expand(g002024^2):

seq(coeff(g, x, i), i=0..degree(g002024)); # Robert Israel, May 30 2017

PROG

(PARI) nn(n)=(sqrtint(n*8)+1)\2;

a(n) = sum(k=1, n, nn(k)*nn(n-k+1)); \\ Michel Marcus, May 30 2017

CROSSREFS

Cf. A002024.

Sequence in context: A312705 A312706 A312707 * A053459 A024398 A054347

Adjacent sequences:  A004794 A004795 A004796 * A004798 A004799 A004800

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified January 18 03:13 EST 2019. Contains 319260 sequences. (Running on oeis4.)