A110534 Number of ways of writing 8n+5 as a sum of 5 odd squares.

1, 1, 1, 2, 2, 2, 3, 3, 2, 4, 4, 3, 5, 5, 4, 6, 6, 4, 7, 7, 5, 8, 8, 7, 9, 9, 6, 10, 10, 8, 11, 11, 10, 12, 13, 8, 13, 14, 11, 14, 14, 12, 15, 16, 12, 16, 18, 14, 18, 18, 14, 20, 20, 14, 19, 20, 16, 21, 24, 19, 21, 24, 18, 23, 24, 20, 24, 27, 23, 26, 25, 20, 29, 30, 23, 25, 31, 26

Offset

0,4

Comments

a(n) is also the number of ways of writing n as a sum of 5 triangular numbers (A000217). - Kenny Lau, Jul 05 2016

Links

Kenny Lau, Table of n, a(n) for n = 0..20000

Prog

(Python)
f = open('b110534.txt', 'w')
N = 20000
n = 1
t = [0]  #triangular numbers
while t[-1] <= N:
    t += [t[-1]+n]
    n += 1
t = t[:-1]
a = [0]*(N+1)  #the sequence
length = len(t)
for i in range(length):
    for j in range(i, length):
        p = t[i] + t[j]
        if p > N: continue
        for k in range(j, length):
            q = p + t[k]
            if q > N: continue
            for l in range(k, length):
                r = q + t[l]
                if r > N: continue
                for m in range(l, length):
                    s = r + t[m]
                    if s > N: break
                    else: a[s] += 1
for index, value in enumerate(a):
    f.write(str(index)+" "+str(value)+"\n")
f.close()
# Kenny Lau, Jul 05 2016

Crossrefs

Cf. A004770.

Sequence in context: A295511 A116505 A381933 * A194340 A194288 A360058

Adjacent sequences: A110531 A110532 A110533 * A110535 A110536 A110537

Keyword

nonn

Author

Philippe Deléham, Sep 03 2005

Extensions

More terms from Don Reble, Sep 17 2005

Status

approved