A303269 Sum of squares of odd digits minus sum of squares of even digits of n.

0, 1, -4, 9, -16, 25, -36, 49, -64, 81, 1, 2, -3, 10, -15, 26, -35, 50, -63, 82, -4, -3, -8, 5, -20, 21, -40, 45, -68, 77, 9, 10, 5, 18, -7, 34, -27, 58, -55, 90, -16, -15, -20, -7, -32, 9, -52, 33, -80, 65, 25, 26, 21, 34, 9, 50, -11, 74, -39, 106, -36, -35, -40, -27

Offset

0,3

Comments

Up to 10^4, resp. 10^5, there are 5824, resp. 59316, positive terms. All terms from a(1) to a(11111) are nonzero: see A076164 for indices of zeros.

Links

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

Maple

f:= proc(n) local t;
  add(t^2*(-1)^(t+1), t=convert(n, base, 10))
end proc:
map(f, [$0..100]); # Robert Israel, Mar 17 2026

Prog

(PARI) A303269(n)=-vecsum(apply(d->d^2*(-1)^d, digits(n)))

Crossrefs

Cf. A076164, A071650, A036301.

Sequence in context: A257587 A257588 A352598 * A003132 A062331 A069940

Adjacent sequences: A303266 A303267 A303268 * A303270 A303271 A303272

Keyword

sign,base

Author

M. F. Hasler, May 18 2018

Status

approved